Skinks make great pets for people who enjoy a low-key, low-maintenance reptile. Once an adult skink is settled in a nice reptile tank, it only requires feeding once or twice a week, changing the water, and monthly cleaning of the terrarium. Owning a skink requires an initial investment in the terrarium, heat lamp, habitat structures, and the pet itself. Once you have supplied these up-front costs, skinks are cheap pets that take little time out of your life.



<h2 id="h-what-are-skinks">What Are Skinks?</h2>



Skinks are one of the most diverse and widely spread families of reptiles in the world. There are <a href="https://www.britannica.com/animal/skink" target="_blank" rel="noopener noreferrer">over 1,200 species</a> of skinks living in tropical, desert, temperate, and arctic climates. Typically, skinks have small legs and a minimal neck and are active during the day. They are <a href="https://www.earth.com/earthpedia-articles/top-3-coolest-underground-reptiles/" target="_blank" rel="noopener noreferrer">burrowing lizards</a> that enjoy being able to dig. Skinks are mostly insectivores, but many species eat fruits and vegetables as part of their diets. The <a href="https://www.australiangeographic.com.au/blogs/creatura-blog/2018/11/the-solomon-islands-skink-is-an-absolute-unit/" target="_blank" rel="noopener noreferrer">Solomon Island Skink</a> is the largest skink in the world, reaching nearly three feet long.



<figure class="wp-block-image alignnone size-full wp-image-1887235"><img src="https://www.earth.com/wp-content/uploads/2020/12/shutterstock_113941807.jpg" alt="" class="wp-image-1887235"/><figcaption>[Clearly, this is a blue-tongued skink.] <a href="https://www.shutterstock.com/g/ladyfoto">ladyphoto</a>/Shutterstock.com</figcaption></figure>



The skinks people typically keep as pets are blue-tongued skinks, which come from Indonesia and Australia. Some people also keep Berber skinks, which are native to northern Africa. People like to keep these skins because they are docile creatures that do well in terrariums. These species of skinks live <a href="https://www.thesprucepets.com/pet-blue-tongued-skinks-1236897#:~:text=They%20are%20docile%2C%20quiet%2C%20gentle,their%20time%20on%20the%20ground." target="_blank" rel="noopener noreferrer">about 15 years</a>, making them long-lived, low-maintenance pets.



<h2 id="h-setting-up-the-skink-tank">Setting Up the Skink Tank</h2>



If you are thinking of getting a skink as a low-maintenance pet, note that you will have to invest some time and money to get the skink settled into your house. Skinks require a handful of objects to live happily and healthfully.



<h3 id="h-a-skink-terrarium">A Skink Terrarium</h3>



First, a skink needs a relatively large terrarium (sometimes called a tank). A 55-gallon tank is the smallest recommended size for a skink, as they like big tanks compared to other lizards. This sized tank would be about eight cubic feet of space, which is about the footprint of a small desk. If you can, get a larger tank! Skinks are active animals. Your skink will have more places to explore and ponder life in a bigger terrarium. Terrariums that open from the front rather than the top are easier to maintain.



<figure class="wp-block-image alignnone wp-image-1887236 size-full"><img src="https://www.earth.com/wp-content/uploads/2020/12/shutterstock_1421683055.jpg" alt="skink" class="wp-image-1887236"/><figcaption>[A pet skink burrows in its substrate.] <a href="https://www.shutterstock.com/g/scink">Scink</a>/Shutterstock.com</figcaption></figure>



<h3 id="h-bedding-and-substrate">Bedding and Substrate</h3>



As mentioned above, skinks are burrowing creatures. This means they need a deep layer of substrate to bury into. This substrate should be no less than six inches deep. <a href="https://www.thebiodude.com/blogs/reptile-and-amphibian-caresheets-with-cited-veterinary-and-herpetology-sources/blue-tongue-skink-care-guide" target="_blank" rel="noopener noreferrer">Various substrates</a> can be used.



<h3 id="h-habitat-structures-caves-logs-sun-rocks">Habitat Structures: Caves, Logs, Sun Rocks</h3>



Do you ever feel like hiding from the world in your room? Skinks are the same way! They need spaces to decompress and feel safe. Reptile companies sell plenty of structures for lizards to hide out in. In addition to hiding places, sinks enjoy rocks to sun on and fun-shaped objects to explore and crawl around on.



<figure class="wp-block-image alignnone size-full wp-image-1887237"><img src="https://www.earth.com/wp-content/uploads/2020/12/shutterstock_1873658005.jpg" alt="" class="wp-image-1887237"/><figcaption>[A skink hangs out in its bamboo cave.] <a href="https://www.shutterstock.com/g/nirut-luechayutthasin">Rut_Luecha</a>/Shutterstock.com</figcaption></figure>



<h3 id="h-the-lizard-heat-lamp">The Lizard Heat Lamp</h3>



<a href="https://www.earth.com/earthpedia-articles/are-amphibians-cold-blooded/" target="_blank" rel="noopener noreferrer">Cold-blooded creatures</a> can only regulate their body temperatures by absorbing heat from their surroundings. In the wild, skinks bask in the sun to gain the energy needed to hunt and move. Houses are too cold for the blue-tongued skinks kept as pets because they prefer temperatures of 90 F. A heat lamp is the best way to warm up your skink's terrarium. Put the heat lamp on one side of the terrarium. This placement makes a hot side and a cold side, which gives the skink options in order to thermoregulate.



<h3 id="h-where-do-i-get-this-stuff">Where Do I Get This Stuff?</h3>



A specialty reptile store will be the best place to buy the required items necessary for starting your skink terrarium. This is especially true if the skink is your first reptile pet. The expert staff at reptile-exclusive stores will know the appropriate tank size, heat lamp power, and type of vitamins to feed to your specific skink. Additionally, these stores will have all the materials you need, making the start-up process quick!



If you are on a budget and looking for second-hand items, there are plenty of terrariums and pet items on websites like NextDoor and Craigslist. Fortunately, once you have the terrarium set up, you are most of the way to caring for your new low-maintenance pet.



<figure class="wp-block-image"><img src="https://www.earth.com/wp-content/uploads/2020/12/shutterstock_1413231470.jpg" alt="" class="wp-image-1887238"/><figcaption><a href="https://www.shutterstock.com/g/dwi-putra-stock">dwi putra stock</a>/Shutterstock.com</figcaption></figure>



<h2 id="h-feeding-skinks">Feeding Skinks</h2>



Once your skink terrarium is set up, you will need to begin regular care of your new pet. Young skinks require feeding more often than adult skinks. Skinks younger than three months should <a href="https://reptifiles.com/blue-tongue-skink-care/blue-tongue-skink-food/" target="_blank" rel="noopener noreferrer">be fed daily</a>. Three to eight-month-old skins should be fed about 3 times per week. For the next 14 years of their lives, skinks only need feeding one to two times per week, making them low-maintenance pets.



In addition to feeding more often, younger skinks require a higher ration of insects in their food than older skinks. Young skinks should eat about 70% insects and 30% vegetables, whereas adult skinks should eat even portions of both.



Some owners swear by <a href="https://reptifiles.com/blue-tongue-skink-care/blue-tongue-skink-food/" target="_blank" rel="noopener noreferrer">cat food and dog food</a>, while others prefer to use live crickets and mealworms. While using live insects is more thrilling for your skink, cat and dog food are certainly a more low-maintenance pet alternative. Skinks like leafy greens and other soft vegetables. While skinks will eat a wide variety of fruits, owners should only feed them fruit as a special treat.



<figure class="wp-block-image alignnone size-full wp-image-1887239"><img src="https://www.earth.com/wp-content/uploads/2020/12/shutterstock_1607384131.jpg" alt="" class="wp-image-1887239"/><figcaption>[A young boy enjoys looking at a reptile in a large terrarium.] <a href="https://www.shutterstock.com/g/galitskaya">Elizaveta Galitckaia</a>/Shutterstock.com</figcaption></figure>



<h2 id="h-low-maintenance-pets-do-require-some-cleaning">Low-Maintenance Pets Do Require Some Cleaning</h2>



The biggest regular maintenance of any low-maintenance reptile is cleaning the terrarium. Every day or so you should change the water, pick out any uneaten food, and pick up any feces. Skinks tend to get their water bowls quite dirty, so some may require their water to be changed daily.



More comprehensive cleaning is required each month. To perform a deep clean you will need to remove everything from the tank, then <a href="https://www.petcoach.co/article/habitats-cleaning-and-disinfecting-reptile-cages/" target="_blank" rel="noopener noreferrer">clean and disinfect each surface</a>. Pay special attention to the corners where grime can build up. If the substrate looks dirty, replace it. Cleaning the skink tank shouldn't take more than an hour or two a month, which is part of the reason these reptiles are great low-maintenance pets.



<h2 id="h-what-are-other-low-maintenance-pets">What Are Other Low-Maintenance Pets?</h2>



Other small lizards, certain birds, and guinea pigs are <a href="https://www.earth.com/earthpedia-articles/low-maintenance-pets/" target="_blank" rel="noopener noreferrer">excellent alternatives</a> to skinks as low-maintenance pets. When considered a pet, be sure to think about expenses, your long-term plans, your space, your interest, and your schedule. When all these factors line up and point you towards a skink, it's probably time you got yourself this lovely reptilian companion.



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Blue-Tongued Skinks: Low Maintenance Pets

Skinks make great pets for people who enjoy a low-key,...

Axolotls have captured the imagination of biologists and science enthusiasts alike. These endangered amphibians can be extremely hard to find, and, unfortunately, may not be around forever. Today, let’s take a deeper dive: what is an axolotl?
<h2>Amphibian Taxonomy</h2>
The axolotl goes by many names. Scientifically, it is referred to as Ambystoma mexicanum. More commonly, it’s called the Mexican walking fish. But, this is a misnomer. While axolotls do in fact walk, they are not fish. They are part of the class Amphibia, meaning that they are <a href="https://www.earth.com/earthpedia-articles/why-are-some-endangered-amphibians-going-extinct/" target="_blank" rel="noopener noreferrer">amphibians</a>. 

The genus that axolotls are part of, Ambystoma, contains 32 species. Collectively, they are referred to as the “mole salamanders.” Aside from the axolotl, the most famous member of this genera is the tiger salamander. Oddly enough, the tiger salamander is the state amphibian of several different states including <a href="https://statesymbolsusa.org/symbol-official-item/kansas/state-amphibian/barred-tiger-salamander" target="_blank" rel="noopener noreferrer">Colorado and Kansas</a>.
<h2><img class="alignnone size-large wp-image-1882394" src="https://www.earth.com/wp-content/uploads/2020/07/axolotl-2193310_1280-1024x768.jpg" alt="axolotl blue" width="1024" height="768" /></h2>
<h2></h2>
<h2>Morphology and Biology</h2>
Several key characteristics identify axolotls. Due to their relatively restricted habitat (more on that later), most axolotls look very similar. 
<ul>
 	<li style="font-weight: 400;">Body size: these are large amphibians! To many people, axolotls may look like very large salamanders, as they are usually around 9 inches long. </li>
 	<li style="font-weight: 400;">Eyes: like all mole salamanders, axolotls have “buggy”, protruding eyes. They lack lids and are almost always black in color.</li>
 	<li style="font-weight: 400;">Gills: external <a href="https://www.earth.com/earthpedia-articles/how-do-amphibians-breathe/" target="_blank" rel="noopener noreferrer">gills</a> are possibly the easiest identifier of an axolotl. This strange, stringy organ hangs off the back of the amphibian’s neck, almost like a <a href="https://animals.sandiegozoo.org/animals/axolotl#:~:text=The%20axolotl%20remains%20aquatic%20(like,fin%2C%20and%20lack%20moveable%20eyelids." target="_blank" rel="noopener noreferrer">colorful necklace</a>.</li>
</ul>
Most axolotls on planet earth are in captivity. Because of this, relatively little is known about the specific habits and group dynamics of wild axolotls. That said, we do know several interesting things about their wild behavior.
<ul>
 	<li style="font-weight: 400;">Predators: axolotls are born hunters. While they will usually hide during the day, axolotls come out at night to feed on small crustaceans, fish, and worms.</li>
 	<li style="font-weight: 400;">Suction eating: the salamanders are capable of sucking up worms and small prey through the mud and gravel of their habitat. Incidentally, they will often take in small bits of gravel and sand. This isn’t harmful to the axolotl, in fact, it is a necessary step for successful digestion. </li>
 	<li style="font-weight: 400;">Parental care: like almost all salamanders, the parents do almost nothing to care for their young. The father is only present for mating. </li>
</ul>
<h2>Coloration</h2>
The different colors of axolotls have been the topic of<a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1432-0436.1984.tb01393.x" target="_blank" rel="noopener noreferrer"> intense genetic research</a>. Researchers from the University of Kansas and Indiana University have been studying this topic for several years. They state that “Four genes are known to affect pigmentation in the Mexican axolotl.” Each one of these genes is recessive. Almost certainly, this is what produces the interesting variety of different colors that we today. 
<ul>
 	<li style="font-weight: 400;">Wild Type: this is the most common coloration of axolotls. Their skin is generally dark, ranging from dark olive-green to almost black. On top of the dark coloration, these types of amphibians also have small golden or silver flecks. This tends to give them a sort of mottled appearance.</li>
 	<li style="font-weight: 400;">Melanoid: the only difference is that the melanoid coloration lacks the gold or silver flecks and is thus entirely dark. Due to this, it can be easy to confuse the wild type coloration with melanoid.</li>
 	<li style="font-weight: 400;">Axunthic: this is another phenotype that can be difficult to distinguish. Axunthic coloration is the result of the lack of a gene that helps to produce and store yellow pigment. As such, these axolotls tend to look more blue than green but are still largely dark.</li>
 	<li style="font-weight: 400;">Albino: this one mostly speaks for itself. Albino axolotls are unable to produce any pigment and are thus white.</li>
 	<li style="font-weight: 400;">White: somewhat surprisingly, this is different than albino. Whereas the albino phenotype lack the ability to produce pigment, white axolotls actually produce white pigment. This causes them to be a more pure color or white. </li>
</ul>
<img class="alignnone size-large wp-image-1882391" src="https://www.earth.com/wp-content/uploads/2020/07/xochimilco-5366272_1280-1024x574.jpg" alt="Lake Xochimilco" width="1024" height="574" />

Image by <a href="https://pixabay.com/users/kinenriquez-1522280/" target="_blank" rel="noopener noreferrer">KinEneiquez</a> via Pixabay

<h2>Axolotl Habitat</h2>
Axolotls are only native to a small portion of Mexico. Presently, they live in a single lake just south of <a href="https://www.earth.com/video/mexico-city-from-space/" target="_blank" rel="noopener noreferrer">Mexico City</a>: <a href="https://www.britannica.com/place/Xochimilco" target="_blank" rel="noopener noreferrer">Lake Xochimilco</a>. As of 2020, the lake exists as a series of canals that run near the outskirts of town. Previously, Xochimilco was much larger, and it was actually a series of lakes. 

According to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0006320709003103" target="_blank" rel="noopener noreferrer">researchers</a> at the Universidad Nacional Autonoma de Mexico, the axolotls “have seen alarming decline in the last decades owing to habitat loss caused by urban growth.” Additionally, In recent surveys of their populations, a staggeringly low count of 23 axolotls were caught for monitoring and release. This number is down from several thousand only a few decades ago.
<h2>Growth and Regeneration</h2>
Axolotls are the subject of intense biology research. This is primarily due to their unique ability to regenerate parts of their body. Various <a href="https://www.nature.com/articles/nature08152" target="_blank" rel="noopener noreferrer">studies</a> have shown that the salamanders have the ability to regrow most parts of their body, even if the entire limb was removed. Axolotls have been shown to regenerate eyes, legs, feet, parts of their heart, and even <a href="https://neuraldevelopment.biomedcentral.com/articles/10.1186/1749-8104-8-1" target="_blank" rel="noopener noreferrer">parts of their brain</a>. This makes them a unique animal model to understand growth and development in humans.

Featured image by <a href="https://pixabay.com/users/uthlas-5660052/" target="_blank" rel="noopener noreferrer">uthlas</a> via Pixabay.

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What Is an Axolotl?

Axolotls have captured the imagination of biologists and science enthusiasts...

The term “osmosis” may bring back nightmares from high school biology. Many people might remember that it has something to do with water… and something to do with cells. This omnipresent process is occurring all around us, constantly. Scientists and industries have learned to manipulate this phenomenon in all manners of interesting applications. Today, let’s break the biology textbook back open and take a moment to better understand: what is osmosis?
<h2>Understanding Osmosis</h2>
Osmosis has many practical utilities in both industry and nature. Before we understand how osmosis functions in real life, let’s first take a look at the definition of osmosis and some easy-to-understand examples.
<h3>Vocabulary</h3>
First, let’s get familiar with some vocabulary that will be necessary to understand the technical definition of osmosis. 
<ul>
 	<li style="font-weight: 400;">Solvation: the process of dissolving something in a liquid. When making hot chocolate, the powder dissolves into the water via the process of solvation.</li>
 	<li style="font-weight: 400;">Solvent: the liquid that does the dissolving. In the above example, the water is acting as the solvent.</li>
 	<li style="font-weight: 400;">Solute: the substance that is being dissolved. In the above example, the hot chocolate powder is acting as the solute.</li>
 	<li style="font-weight: 400;">Semipermeable membrane: a filter of sorts that selectively lets some substances through, but does not allow others to pass. For example, a window screen is a type of semipermeable membrane. Air, water, and dust can all move through the screen, but a cat, coffee mug, or computer cannot pass through.</li>
</ul>
<h3>Definition</h3>
Okay, now we’re ready! As defined by <a href="https://www.merriam-webster.com/dictionary/osmosis" target="_blank" rel="noopener noreferrer">Merriam-Webster</a>, osmosis is the “movement of a solvent (such as water) through a semipermeable membrane… into a solution of higher solute concentration that tends to equalize the concentrations of solute on the two sides of the membrane.”

Take a look at the diagram below to help understand.

<img class="alignnone size-full wp-image-1882078" src="https://www.earth.com/wp-content/uploads/2020/06/Osmosis-semi-permeable-membrane.jpg" alt="Osmosis semi-permeable membrane" width="544" height="260" />
[Diagram courtesy of <a title="via Wikimedia Commons" href="https://commons.wikimedia.org/wiki/File:0307_Osmosis_cleaned.jpg" target="_blank" rel="noopener noreferrer">OpenStax</a> / <a href="https://creativecommons.org/licenses/by/3.0" target="_blank" rel="noopener noreferrer">CC BY</a>]

The pink liquid in the beaker exists on both sides of the semi-permeable membrane (the dotted red line). Notice that the concentration of the solute (the small spheres) is higher on the right-hand side than the left-hand side. There are about 7 spheres on the left-hand compared to about 30 on the right-hand side. The solvent will move from left (lower solute concentration) to right (higher concentration) in order to equalize the concentrations. Note that the solute particles do not move - only the liquid solvent.
<h2>Osmosis Examples</h2>
Armed with a working definition, let’s examine some easy-to-understand examples of osmosis.

[caption id="attachment_1882080" align="alignnone" width="1024"]<img class="size-large wp-image-1882080" src="https://www.earth.com/wp-content/uploads/2020/06/food-624603_1920-1024x679.jpg" alt="Raisins osmosis" width="1024" height="679" /> [Image by <a href="https://pixabay.com/users/forwimuwi73-519165/" target="_blank" rel="noopener noreferrer">Forwimuwi73</a> via <a href="https://pixabay.com/" target="_blank" rel="noopener noreferrer">Pixabay</a>][/caption]
<h3>Raisin in Water</h3>
This is an experiment that is easy to try at home. Take a few raisins and place them into a cup of <a href="https://www.earth.com/news/tap-water-contaminants/">tap water</a>. Come back 30 minutes later and what will you see? The raisins will have swollen to a larger size. Why? Osmosis. The water contains fewer solutes (like sodium, potassium, and magnesium) than the raisin. In response, the water moves from low solute concentration (the tap water) to high solute concentration (the raisin).
<h3>Sore Throats</h3>
An <a href="https://www.mayoclinic.org/diseases-conditions/strep-throat/diagnosis-treatment/drc-20350344#:~:text=Gargle%20with%20warm%20salt%20water,out%20the%20liquid%20after%20gargling." target="_blank" rel="noopener noreferrer">oft-cited remedy</a> for a sore throat is to gargle salt water. This can be very beneficial, and it is an example of osmosis. When you have a sore throat, the cells in the back of your throat are often swollen, filled with water. When you mix salt into tapwater, it creates a somewhat concentrated saline solution. 

This solution has a higher concentration of solutes (salt) than the cells in the back of your throat. Thus the water moves from low solute concentration (your throat) to high solute concentration (the saltwater). This causes temporary relief from the swelling. 
<h2>Applications of Osmosis</h2>
Osmosis is an important process both in nature and society. Let’s take a closer look at some of the applications and instances of osmosis around us. 
<h3><img class="alignnone size-large wp-image-1882081" src="https://www.earth.com/wp-content/uploads/2020/06/chicken-brine-1024x768.png" alt="chicken brine" width="1024" height="768" /></h3>
[Image by <a title="via Wikimedia Commons" href="https://commons.wikimedia.org/wiki/File:Dry_brining_chicken.png" target="_blank" rel="noopener noreferrer">Lexlex</a> / <a href="https://creativecommons.org/licenses/by-sa/4.0" target="_blank" rel="noopener noreferrer">CC BY-SA</a>]
<h3>Food Preservation</h3>
Osmosis is an age-old technique used to <a href="https://www.almanac.com/content/preserving-meats-salting-and-brining#:~:text=Brining%20Pork,salt%20and%20sugar%20are%20dissolved." target="_blank" rel="noopener noreferrer">preserve meats</a>. Typically, the process is referred to as “<a href="https://www.earth.com/video/desalination-method-will-help-manage-hypersaline-brines/">brining.</a>” Meat is cut into smaller pieces and then encased in a very highly concentrated saltwater solution. 

Over the course of several days or weeks, the water inside the meat will move from low solute concentration (in the meat) to high solute concentration (in the saltwater solution). The loss of water makes the meat an inhospitable place for bacteria to grow, thus helping to preserve the meat. This was a common tactic for sea voyages before the invention of refrigeration. 
<h3>Plants</h3>
Osmosis is what allows <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4097062/" target="_blank" rel="noopener noreferrer">plants to survive</a>. Specifically, the process of osmosis draws water from the roots of the plant to the leaves of the plant. This is accomplished by the usage of a salt gradient. The lowest part of the plant, <a href="https://www.earth.com/news/plant-roots-find-water/">the roots</a>, has the least amount of salt. The highest part of the plant, the leaves, has the highest concentration of salt. This causes water to constantly be drawn upwards towards the leaves.

Plants also use osmosis for other purposes, as well. Specialized cells, called “<a href="https://www.earth.com/news/deeper-look-plants-breathe/">guard cells</a>”, grow and shrink in response to how much water the plant has. When the plant is engorged with water, the cells swell with water and create tiny openings in the leaf. This allows water to escape. When the plant is low on water, the cells shrink, causing that same opening to shut, thus conserving water.
<h2>Osmotic Understanding</h2>
That wasn’t too complex! Do you still have any questions about osmosis? Any relevant examples you’d like to share? Let us know in the comments. 

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What Is Osmosis?

The term “osmosis” may bring back nightmares from high school...

Are Dolphins Smart? How Are Dolphins Intelligent? We humans tend to arrogantly assume our intelligence is leaps and bounds beyond that of any animal. However, other animals, including dolphins, show many signs of intelligence and complex thought.
<h2>Defining Intelligence</h2>
It is obvious that human intelligence has had a huge impact on our planet. Our use of tools and communication has created complex cultures and technologies. Human intelligence has enabled many amazing (and terrible) things.

Though humans are undeniably highly intelligent animals, it is difficult to pin down the traits that distinguish our intelligence from that of other animals. Other animals can use tools, communicate, and even experience complex emotions.

A better question than whether dolphins are smart or not may be HOW are dolphins intelligent? Understanding the areas in which these creatures excel may help us understand intelligence in general.
<h3>Intelligent Behavior</h3>
A popular test of intelligence is the “mirror test,” which tests whether animals acknowledge their reflection. This test demonstrates self-awareness. Though self-awareness is one important element of human intelligence, it is just one piece of the puzzle.

Other behaviors such as communication and the use of tools are signs of intelligence. Social behaviors and complex emotions are also considered signs of intelligence.

Defining intelligence in animals is difficult. A species’ problem-solving techniques vary greatly based on the situations they encounter. It wouldn’t do a dolphin much good to know tons about how to climb trees. However, that certainly doesn’t mean they are less intelligent than squirrels.
<h3>Dolphins</h3>
Dolphins have many intelligent behaviors. They are extremely social animals with complex communication and relationships. Dolphins are able to pass information between generations, teaching skills to their extended family!
<h3>Are Big Brains Better?</h3>
Another popular indicator of intelligence is based on the size of the brain. The ratio of the mass of the body to the brain is a common indicator of intelligence.

This ratio <a href="http://pages.ucsd.edu/~jmoore/courses/allometry/allometry.html" target="_blank" rel="noopener noreferrer">is called the “encephalization quotient” (EQ) and is measured in a number of different ways</a>. It often accurately indicates species that humans deem “intelligent,” but it is far from perfect. It is difficult to compare the EQ of distantly related species like humans and dolphins.

Dolphins are <a href="https://www.youtube.com/watch?v=05PpTqtGhGU" target="_blank" rel="noopener noreferrer">second only to humans</a> in EQ! Though this doesn’t tell us how smart dolphins are, it does support the observations of their intelligence.
<h2>Dolphin Intelligence</h2>
Dolphins and whales show many signs of intelligence and complex thought. This group of aquatic mammals (the Cetaceans) use tools, communicate, and even have funerals! In captivity, these species can be trained to perform complex tasks and even recognize symbols.

Dolphins can understand how the order of words changes their meaning. When taught to recognize symbols, they can differentiate between the phrases “ball to the hoop” or “hoop to the ball.” Dolphins have also been trained for complex tasks such as hunting mines in the ocean.

[caption id="attachment_1878628" align="aligncenter" width="830"]<img class="wp-image-1878628 size-full" src="https://www.earth.com/wp-content/uploads/2019/11/NMMP_dolphin_with_locator.jpg" alt="A dolphin with a device on its flipper jumping out of the water by a man in camo." width="830" height="997" /> K-Dog is a Bottlenose dolphin trained to find mines. He is wearing a "pinger" that helps handlers keep track of him.[/caption]

Dolphins and other cetaceans have complex social lives. They live in family groups and form strong bonds with each other. These groups communicate with each other, and <a href="https://us.whales.org/whales-dolphins/how-do-dolphins-communicate/" target="_blank" rel="noopener noreferrer">even likely give each other unique “names.”</a>

Dolphins also communicate through their interactions. They are able to teach each other complex behaviors. A group of dolphins near Australia has learned to <a href="https://www.sciencemag.org/news/2011/07/why-dolphins-wear-sponges" target="_blank" rel="noopener noreferrer">wear sponges on their beaks to protect them while fishing</a>. Another group of dolphins in <a href="https://www.nationalgeographic.com/animals/2018/07/dolphin-animal-marine-mammal-hunting-video-news/" target="_blank" rel="noopener noreferrer">Florida has learned to create “nets” of mud</a> that they use to herd their prey.
<h3>Empathy as a Sign of Dolphin Intelligence</h3>
Another example of dolphin intelligence is empathy. For example, dolphins mourn the loss of members of their families. In addition, their empathy extends beyond their own species. There are many stories of dolphins coming to the aid of drowning people, carrying them to the surface for air.

These complex behaviors obviously show that dolphins are intelligent. Their social behaviors, communication, empathy, and use of tools reveal their intelligence. Though defining or measuring their intelligence is difficult, it is obvious that these creatures have a lot on their minds!
<h2>Dolphins Deserve Respect</h2>
[caption id="attachment_1878629" align="aligncenter" width="1024"]<img class="size-full wp-image-1878629" src="https://www.earth.com/wp-content/uploads/2019/11/Parc_Asterix_22.jpg" alt="A dolphin in a tank underwater." width="1024" height="768" /> Dolphins in captivity are limited to less than <a href="https://www.sciencemag.org/news/2010/02/dolphin-person" target="_blank" rel="noopener noreferrer">one one-thousandth of 1% of their natural range.</a>[/caption]

With our understanding of Cetacean intelligence comes a responsibility to respect these animals. The lived experience of a dolphin may not be that different from our own. If these animals can empathize with us, it seems we should be able to empathize in return.

We should all do what we can to protect dolphins from hunting, sonar, and abuse. Protecting <a href="https://www.earth.com/earthpedia-articles/what-does-the-bottom-of-the-ocean-look-like/" target="_blank" rel="noopener noreferrer">their habitat</a> is also essential. The oceans are filled with <a href="https://www.earth.com/news/ocean-trash-gulf-mexico/" target="_blank" rel="noopener noreferrer">man-made garbage</a> that kills animals and throws off the <a href="http://earth.com/news/clean-ocean-plastic-threaten-species/" target="_blank" rel="noopener noreferrer">ocean’s delicate ecology</a>.
<h2>Other Brainiacs of the Animal Kingdom</h2>
Dolphins aren’t the only animals that have surprised humans with their intelligence. A number of species have proven to be quite clever.
<ul>
 	<li>Crows <a href="https://www.sciencealert.com/crows-are-so-smart-they-can-make-compound-tools-out-of-multiple-parts" target="_blank" rel="noopener noreferrer">can build tools out of useless parts</a>. They show an understanding of cause and effect and can make complex plans for the future. They can combine learned experience to <a href="https://www.cnet.com/news/watch-a-wild-crow-tackle-a-complex-eight-step-puzzle/" target="_blank" rel="noopener noreferrer">independently solve complex puzzles</a>. These birds also recognize individual human faces, making friends and holding grudges.</li>
 	<li><a href="https://www.earth.com/earthpedia-articles/are-octopuses-smart/" target="_blank" rel="noopener noreferrer">Cephalopods (such as octopuses) are another group of clever aquatic animals</a>. These species can solve mazes, plan daring escapes, use tools, open jars and recognize people! They are more closely related to a clam than a human but have independently evolved a complex nervous system. Their brains are distributed throughout their bodies, clustering in their many legs.</li>
 	<li>Many primates other than humans show advanced intelligence. <a href="https://www.earth.com/news/chimpanzees-communicate-human-language/" target="_blank" rel="noopener noreferrer">Chimpanzees and other great apes use language</a> and have complex social lives. They can be trained to communicate with humans using signs. <a href="https://www.smithsonianmag.com/science-nature/what-can-chimpanzee-calls-tell-us-about-origins-human-language-180969027/" target="_blank" rel="noopener noreferrer">Like dolphins, different groups of chimpanzees </a>have different ‘dialects.’</li>
</ul>
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Are Dolphins Smart? How Are Dolphins Intelligent?

Are Dolphins Smart? How Are Dolphins Intelligent? We humans tend...

Reptiles first walked the earth about 300 million years ago and have since diversified into over 10,000 extant (living) species. These animals live on six continents on earth, in a variety of bizarre and unique locations. Lizards, snakes, crocodiles, and caimans are all reptiles - but are turtles reptiles? 
<h2>What Are Turtles?</h2>
All turtles have a few things in common. First, they evolved during the <a href="https://ucmp.berkeley.edu/education/explorations/tours/intro/Intro5to12/tour2d.php" target="_blank" rel="noopener noreferrer">Middle Jurrasic</a> period about 160 million years ago. Additionally, they also all have a ‘shell’ of some kind. For some turtles, this is a classic hard, bony shell and for others, this is a relatively soft shell. 

Secondly, let’s clarify some terminology. What exactly is a turtle? Turtles all fall into the order Testudines. They are on the <a href="https://culter.colorado.edu/~kittel/WEcol_Handouts/MammalOrders_Sheryn06.pdf" target="_blank" rel="noopener noreferrer">same level of biological classification</a> as marsupials (kangaroos, opossums), carnivores (wolves, hyenas), and cetaceans (whales, dolphins). All turtles fit into one of two suborders: cryptodirans or pleurodirans. The distinction lies in the manner that each suborder covers their head and neck. The former simply pulls their head straight back into the shell. The latter need to turn their head to the side to retract it into the shell. 
<h2><img class="alignnone size-large wp-image-1876962" src="https://www.earth.com/wp-content/uploads/2019/08/giant-tortoises-2872006_1280-1024x602.jpg" alt="galapagos tortoise" width="1024" height="602" /></h2>
<h2>Types of Turtles</h2>
From there, 14 families of Testudines exist today. Let’s take a look at some of the more well-known examples. 
<ul>
 	<li style="font-weight: 400;">Cheloniidae: This family, commonly known as "sea turtles," includes five genera with six species. When conservation groups protect seashores in the name of turtles, they're typically protecting members of Cheloniidae like loggerheads and green sea turtles. </li>
 	<li style="font-weight: 400;">Chelydridae: Anytime you hear of a turtle being referred to as a ‘snapping turtle’, it's probably in reference to one of the five species of Chelydridae. One of the largest species of Chelydridae is the alligator snapping turtle (Macrochelys temminckii), which can weigh <a href="https://www.nationalgeographic.com/animals/reptiles/a/alligator-snapping-turtle/" target="_blank" rel="noopener noreferrer">up to 100 kilograms</a> (220 lbs).</li>
 	<li style="font-weight: 400;">Dermochelyidae: One species of sea turtle is very different from Cheloniidae: the leatherback sea turtle. As its name implies, the leatherback can be differentiated from other sea turtles by its lack of a hard shell. Instead, it has an oily skin on its back. These turtles can grow to be <a href="https://oceanservice.noaa.gov/facts/leatherback.html" target="_blank" rel="noopener noreferrer">over two meters</a> (seven feet) long and weigh over 900 kilograms (2,000 lbs)!</li>
 	<li style="font-weight: 400;">Emydidae: The roughly 50 species of Emydidae are sometimes referred to as terrapins. Collectively, they make up the freshwater and pond turtles. Typically, pet stores will sell any number of the species of Emydidae.</li>
 	<li style="font-weight: 400;">Testudinidae: Contrary to popular belief turtles are not tortoises- it’s the other way around. In reality, all tortoises are turtles. Tortoises are simply members of the family Testudinidae within order Testudines.</li>
</ul>
<h2><img class="alignnone wp-image-1876963 size-large" src="https://www.earth.com/wp-content/uploads/2019/08/turtles-3289690_1280-1024x712.jpg" alt="are turtles reptiles?" width="1024" height="712" /></h2>
<h2>What Are Reptiles?</h2>
Now that we understand where turtles fall in terms of biological classification, let’s turn to reptiles. During the <a href="https://www.earth.com/news/coal-earth-ice/" target="_blank" rel="noopener noreferrer">carboniferous period</a> roughly 300 million years ago, the first pseudo-reptiles called reptiliomorphs evolved on earth. This group of organisms slowly adapted to living on dry land, as opposed to partially in water like their ancestors, the amphibians. 

Reptiles are all marked by a few specific features. Let’s take a look.
<ul>
 	<li style="font-weight: 400;">Cold-blooded: there are many different ‘ways’ for an organism to be cold-blooded: ectothermy, <a href="https://link.springer.com/chapter/10.1007%2F978-3-642-65708-5_10" target="_blank" rel="noopener noreferrer">poikilothermy</a>, and bradymetabolism are just a few. All reptiles exhibit some form of this, meaning that they do not have total control of their internal body temperature and utilize external sources to make up for this fact. </li>
 	<li style="font-weight: 400;">Lungs: all reptiles breath using lungs. This is a significant difference between amphibians and reptiles. Amphibians evolved a variety of ways to breathe without lungs, sometimes even diffusing air <a href="https://www.earth.com/earthpedia-articles/how-do-amphibians-breathe/" target="_blank" rel="noopener noreferrer">through their skin</a>. While we know that turtles have lungs, expanding them with a hard shell is difficult. During periods of hibernation, some species of turtles actually submerge themselves in water - how can they breathe with lungs? Turns out, turtles utilize a form of respiration known as <a href="https://www.int-res.com/abstracts/meps/v340/p287-298/" target="_blank" rel="noopener noreferrer">cloacal respiration</a>. Essentially, they pass oxygenated water across body surfaces that contain many blood vessels.</li>
 	<li style="font-weight: 400;">Skin: reptiles are also marked by a watertight skin that falls between amphibian skin and mammalian skin in terms of toughness. Unlike amphibians who need to breathe through their skin, reptiles live primarily on dry land, only going into the water when necessary. Unlike mammals, their skin isn’t nearly as thick, and thus offers less protection.</li>
</ul>
<h2><img class="alignnone size-large wp-image-1876964" src="https://www.earth.com/wp-content/uploads/2019/08/turtle-1593875_1920-1024x681.jpg" alt="deep sea turtle" width="1024" height="681" /></h2>
<h2>Are Turtles Reptiles?</h2>
All turtles are reptiles! In fact, turtles are some of the oldest reptiles still living on planet earth. They evolved around <a href="https://blogs.scientificamerican.com/tetrapod-zoology/letters-from-the-world-of-turtle-evolution/" target="_blank" rel="noopener noreferrer">220 million years ago</a> - only 80 million years after the very first reptiles. Turtles make up a unique order in that their habitats vary widely. Some turtles, like the green turtle (Chelonia mydas), have been shown to migrate <a href="https://conbio.onlinelibrary.wiley.com/doi/abs/10.1111/cobi.12325" target="_blank" rel="noopener noreferrer">over 3979 kilometers</a> (2500 miles) across open ocean! Other turtles, like the Aldabra giant tortoise (Aldabrachelys gigantea) live their entire lives almost exclusively on land. 

Turtles are part of a unique group of animals that are survivors - species and families that have stood the test of time. Not many other organisms that are complex as turtles have been around for as long. But current trends in pollution, habitat destruction, and irresponsible land use continue to put these and other animals at risk. Almost <a href="https://www.worldwildlife.org/species/sea-turtle" target="_blank" rel="noopener noreferrer">every species of turtle</a> is listed as endangered by the World Wildlife Foundation. Consider <a href="https://www.earth.com/take-action-save-earth/" target="_blank" rel="noopener noreferrer">contributing to organizations</a> that help protect the habitat and resources necessary for turtles to fight for their survival.

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Are Turtles Reptiles?

Reptiles first walked the earth about 300 million years ago...

The mushroom kingdom (Eumycota) is extremely diverse. Species of fungus provide powerful medicines, key ecosystem services, and some showy displays. Scientists group fungi together due to their shared evolutionary history. One unique trait that unites these related organisms is their cell wall. This fungal skeleton has a unique composition, not found in any other type of cell.

Though the classic red and white toadstool of Amanita muscaria is most closely associated with Eumycota, this kingdom includes species that occur throughout nature. Fungi grow between the cells of nearly every plant. They provide nutrient flow and chemical signaling between trees through the forest floor. They also break down dead matter, recycling nutrients back into the ecosystem. These many services are all done by cells protected by the unique fungal cell wall.

&nbsp;
<h2>What Is a Cell Wall?</h2>
&nbsp;

[caption id="attachment_1876670" align="aligncenter" width="1443"]<img class="size-full wp-image-1876670" src="https://www.earth.com/wp-content/uploads/2019/08/PlantCells.jpg" alt="An image of a plant root cross section under a light microscope. The colors come from added stains, highlighting cell walls and other structures." width="1443" height="1420" /> A dyed root cross-section under a microscope. Each curved polygon is a plant cell. Photo by <a href="https://www.caseyhofford.com" target="_blank" rel="noopener noreferrer">Casey Hofford</a>.[/caption]

&nbsp;

Cells are the most basic unit of life (<a href="https://www.earth.com/news/origins-life-simple-molecules/" target="_blank" rel="noopener noreferrer">though viruses and self-replicating RNA</a> deserve some consideration as well). These tiny pockets of genetic information and molecular machinery are the building blocks of everything from your fingers to the petals of flowers. Cells come in many shapes and sizes. Fungi, plants, animals, and bacteria each have unique cellular features.

Though <a href="https://www.earth.com/news/eukaryotic-cells-origin/" target="_blank" rel="noopener noreferrer">all eukaryotic cells have organelles</a>, a nucleus, and a plasma membrane, only plants and fungi have cell walls. These walls provide rigidity and structure to their cells. While most animal cells are soft, requiring bones to give them structure, plants, and fungi get their structure from their cells’ walls.

&nbsp;
<h2>The Structure of Fungi</h2>
&nbsp;

[caption id="" align="alignnone" width="884"]<img src="https://upload.wikimedia.org/wikipedia/commons/3/31/Oyster_mushroom_%28Pleurotus_ostreatus%29_mycelium_in_petri_dish_on_coffee_grounds.JPG" alt="An oyster mushroom's mycelium growing out through coffee grounds. All credit for this photo goes to Tobi Kellner on Wikimedia Commons." width="884" height="663" /> This mycelium includes millions of individual threads of hyphae, providing a huge surface area. Photo by <a href="https://commons.wikimedia.org/wiki/File:Oyster_mushroom_(Pleurotus_ostreatus)_mycelium_in_petri_dish_on_coffee_grounds.JPG" target="_blank" rel="noopener noreferrer">Tobi Kellner</a>.[/caption]

&nbsp;

Though we generally think of fungi as being umbrella-shaped toadstools, these are simply the reproductive organs of the fungi. Fungi spend most of their lives as a network of thin fibers called mycelium. This mycelium is made up of many thin strands of fungal cells, called hyphae. These cells wind through decomposing matter, secreting digestive enzymes and slowly consuming the resulting nutrients through osmosis.

These thin fungal cells provide a huge surface area. With all this exposed surface area, a cell wall is essential for protection. The cell wall provides more than just structure to fungi. It is also the outermost barrier between the fungi and the outside world. Therefore, it plays an essential role in protecting the fungi from pathogens and toxins. The complex mixture of chitin, glucans, and proteins blocks large particles. <a href="https://www.asmscience.org/content/journal/microbiolspec/10.1128/microbiolspec.FUNK-0035-2016" target="_blank" rel="noopener noreferrer">Proteins allow fungi to remodel the cell wall</a> and to interact with the outside world.

The <a href="http://www.botany.hawaii.edu/faculty/wong/Bot201/Myxomycota/Introduction.htm" target="_blank" rel="noopener noreferrer">fungal cell wall is outside of the cell membrane</a>. The cell membrane is the semi-fluid layer that creates the boundary between the cell and the outside world. Within this thin barrier, all of the cells essential organelles, proteins, and nutrients float through the cytosol. The cell wall <a href="https://www.ncbi.nlm.nih.gov/books/NBK8099/" target="_blank" rel="noopener noreferrer">provides external protection</a> for this soft barrier.

&nbsp;
<h2>Septate and Coenocytic Fungi</h2>
<a href="https://ucmp.berkeley.edu/fungi/fungimm.html" target="_blank" rel="noopener noreferrer">Two different structures of the fungal cell wall</a> define two different categories of fungi.
<ul>
 	<li>Coenocytic fungi do not build cell walls between the nuclei of their hyphae. Under a microscope, these hyphae appear as single long cells with many nuclei.</li>
 	<li>Septate fungi form cell walls between the cells of their hyphae, called septa.</li>
</ul>
&nbsp;
<h2>How Do Fungi Differ from Plants?</h2>
Fungi were once thought to simply be a type of plant. As recently as the 1960s, scientists considered fungi to be a type of plant, within the kingdom Plantae. This seems like a rational guess. Plants and fungi are both stationary, rooted to the ground. Though this seems like an important observation, the way species collect their nutrients is far more important.

Plants are all (or nearly all) capable of collecting energy from sunlight through photosynthesis (autotrophs). Fungi, like animals, must consume other life to get energy (heterotrophs). Fungi are heterotrophic, not autotrophic, and they generally decompose and absorb dead life. Though they don’t hunt or graze like many animals, this “saprophytic” style of eating is more similar to animals than plants.

&nbsp;
<h2>What Are Fungal Cell Walls Made Of?</h2>
[caption id="" align="alignnone" width="960"]<img src="https://upload.wikimedia.org/wikipedia/commons/2/24/Cell_wall_structure_of_Fungi.png" alt="An illustration of a fungal cell wall showing the cell membrane at the bottom. Chitosan and glucans next, an amorphous matrix and a surface coat of glycoproteins." width="960" height="720" /> This diagram shows the basic structure of a fungal cell wall. All credit goes to <a href="https://commons.wikimedia.org/wiki/File:Cell_wall_structure_of_Fungi.png" target="_blank" rel="noopener noreferrer">the original uploader on Wikimedia Commons</a>.[/caption]

&nbsp;

A unique mixture of chemicals makes up fungal cell walls. These include chitin, a derivative of glucosamine. This substance is not found in plants. Other than fungi, chitin is only found in animals such as in the exoskeletons of <a href="https://www.earth.com/earthpedia-articles/are-insects-animals/" target="_blank" rel="noopener noreferrer">arthropods (insects</a> and crustaceans.) Chitin is a tough molecule that can form into long chains and meshes, providing a 3D skeleton around fungal cells.

The structural chitin in fungal cell walls is unique. <a href="https://www.thoughtco.com/cell-wall-373613" target="_blank" rel="noopener noreferrer">Plant cell walls use cellulose</a> to build their structure. This is what provides the structure to plant-derived products like wood and paper.

&nbsp;

In conclusion, yes, fungi have cell walls, but not of the same sort as plants. Fungi are a distinct kingdom of life. Their characteristics, life habits, and cellular structure are different from both plants and animals.

Do Fungi Have Cell Walls?

The mushroom kingdom (Eumycota) is extremely diverse. Species of fungus...

Before Leonardo da Vinci was a painter he studied anatomy. His mentor, Andrea del Verrocchio, believed that anatomy was essential to the master painter, and da Vinci agreed, <a href="https://books.google.com/books?id=P1FwDwAAQBAJ&amp;printsec=frontcover&amp;source=gbs_ge_summary_r&amp;cad=0#v=onepage&amp;q&amp;f=false" target="_blank" rel="noopener noreferrer">writing</a> “It is necessary for a painter to be a good anatomist, so that he may be able to design the naked parts of the human frame and know the anatomy of the sinews, nerves, bones, and muscles.” 

Even in the 15th century, scientists and painters alike wondered “what are humans made of?” The question is complicated at the very least, so let’s look at a few different ways of dissecting what really is inside of us all.

&nbsp;
<h2><img class="alignnone size-large wp-image-1876642" src="https://www.earth.com/wp-content/uploads/2019/08/wave-4408564_1280-1024x682.jpg" alt="atoms molecules" width="1024" height="682" /></h2>
&nbsp;
<h2>Atomically</h2>
Really, aren’t we all just a collection of atoms and molecules? For as complicated as humans (and other life) are, <a href="https://play.google.com/store/books/details?id=A9XTBwAAQBAJ&amp;rdid=book-A9XTBwAAQBAJ&amp;rdot=1&amp;source=gbs_vpt_read" target="_blank" rel="noopener noreferrer">99% of our bodies</a> are composed of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. 

There are two big ways to look at how ‘much’ of humans is a specific element: mass and atomic percent. The former is simply what percent of the weight in a human comes from a certain element. Through this lens, oxygen easily takes the cake with 65% of our mass! Considering oxygen’s relatively heavy mass (16g/mol) as well as the huge quantities of water (H2O) and oxygen gas (O2) in our bodies, this makes sense. 

If we instead look through the latter lens of atomic percent, oxygen is no longer king. In this instance, hydrogen is the most common, making up about 62% of all atoms in our bodies. Hydrogen atoms are in practically all organic molecules in our bodies: fats, carbs, <a href="https://www.earth.com/news/dna-first-farmers-east-africa/" target="_blank" rel="noopener noreferrer">DNA</a>, and proteins. For comparison, nitrogen is the fourth most common element in our bodies, but only makes up 1% of all atoms.

&nbsp;
<h2><img class="alignnone size-large wp-image-1876643" src="https://www.earth.com/wp-content/uploads/2019/08/red-blood-cells-3188223_1920-1024x614.jpg" alt="red blood cells" width="1024" height="614" /></h2>
&nbsp;
<h2>Cellularly</h2>
The average human has about <a href="https://www.ncbi.nlm.nih.gov/pubmed/23829164" target="_blank" rel="noopener noreferrer">30,000,000,000,000 (30 trillion) cells</a> in their body. Well, 30 trillion human cells. Along with those, there are about 38 trillion <a href="https://www.earth.com/news/bacteria-travel-thousands-miles/" target="_blank" rel="noopener noreferrer">bacterial cells</a>. Yes, by pure cell count, we are <a href="https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002533" target="_blank" rel="noopener noreferrer">more bacterial than human</a>! These bacteria are immensely important for all sorts of basic<a href="https://www.earth.com/earthpedia-articles/what-is-microbiomics/" target="_blank" rel="noopener noreferrer"> human functions</a> from <a href="https://www.nih.gov/news-events/nih-research-matters/bacteria-skin-boost-immune-cell-function" target="_blank" rel="noopener noreferrer">defense</a> to <a href="https://www.anl.gov/article/exploring-the-role-of-gut-bacteria-in-digestion" target="_blank" rel="noopener noreferrer">digestion</a>. 

If we just focus on human cells, there are about <a href="https://www.nature.com/scitable/blog/bio2.0/discovering_new_cell_types_one/" target="_blank" rel="noopener noreferrer">200 different cell types</a>. Out of all 200, the vast majority of them are found in our blood. About 84 of every 100 cells is an erythrocyte - also known as a red blood cell. The next largest category is <a href="https://www.urmc.rochester.edu/encyclopedia/content.aspx?ContentTypeID=160&amp;ContentID=36" target="_blank" rel="noopener noreferrer">platelets</a> - making up about 5% of our cells. The remaining 10% of our cells are split amongst the rest of the cell types, like neurons, muscle cells, fat cells, and skin cells. 

&nbsp;
<h2><img class="alignnone size-large wp-image-1876644" src="https://www.earth.com/wp-content/uploads/2019/08/anatomical-2261006_1920-1024x683.jpg" alt="people anatomy" width="1024" height="683" /></h2>
&nbsp;
<h2>Organ Systems</h2>
How much does your spleen weigh? How about an average pinky toe? A <a href="https://www.ncbi.nlm.nih.gov/pubmed/22182983" target="_blank" rel="noopener noreferrer">series</a> of <a href="https://www.ncbi.nlm.nih.gov/pubmed/22182984" target="_blank" rel="noopener noreferrer">studies</a> published in 2012 attempted to establish ‘normal’ ranges for major organs in the human body. They used only males, and the average weight was approximately 75 kg (165 lb). Humans like to think of themselves as pretty smart - and if mass is anything to judge by, they are just off. While the average brain in the study weighed 1.41 kg, (that’s 3.11 pounds or about 2% of total body mass) the average <a href="https://www.earth.com/earthpedia-articles/liver/" target="_blank" rel="noopener noreferrer">liver</a> was slightly heavier - 1.56 kg (3.44 lb)! Other noteworthy heavy organs were the lungs (.84 kg together), heart (.31 kg), and kidneys (.26 kg together).

When we start to look at the various surface areas of organs, the question of ‘biggest’ becomes even more interesting. The common adage ‘the skin is the largest organ’ is very far from true. While the average 70kg man has a total skin surface area of 1.7m2, this is far from the largest. Studies have shown the air-exchanging surface of the lungs to be 70m2, approximately half the size of a tennis court. Furthermore, the mucosal surface of the human GI tract is estimated to be approximately the size of a football field!

&nbsp;
<h2>Stardust</h2>
13.8 billion years ago, the <a href="https://www.earth.com/earthpedia-articles/cosmology/" target="_blank" rel="noopener noreferrer">big bang</a> occurred and put everything into existence that ever was or ever will be. Several hundred thousand years after that event, simple atoms began to form, namely hydrogen and helium. Gradually, gravitational forces pulled those atoms together into super-dense, super-hot swirling clouds of particles. Stars begin to form all over the universe, eventually numbering into the billions. 

<iframe width="560" height="315" src="https://www.youtube.com/embed/xIV-k39Kukw" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

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At the center of these stars (and modern stars, as well) is the core - where hydrogen is turned into helium. Massive amounts of energy are released during this process, providing the building blocks for other elements that we know today: carbon, oxygen, and nitrogen. These stars are the ultimate source for every single non-hydrogen and non-helium atom in our known universe. What are humans made of? Through the lens of the big bang, we’re made of stardust! 

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What Are Humans Made Of?

Before Leonardo da Vinci was a painter he studied anatomy....

The earth is very very old. About 4.5 billion years old. To help understand what has been happening all those years, the <a href="http://www.stratigraphy.org/" target="_blank" rel="noopener noreferrer">International Commission on Stratigraphy</a> (ICS), part of the <a href="https://www.iugs.org/" target="_blank" rel="noopener noreferrer">International Union of Geological Sciences</a> (IUGS), has developed a system called the <a href="https://www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx" target="_blank" rel="noopener noreferrer">geologic time scale</a> (GTS). 

The original concept of geologic time dates all the way back to Aristotle and da Vinci. The modern interpretation has been in common science usage only since the mid-20th century. The GTS takes the last 4.5 billion years of earth history and divides them into various time periods. This includes 2 supereons, 4 eons, 14 eras, 22 epochs, and over 100 ages. 

Presently, there is a scientific debate about which epoch we are in. The discussion centers around the Holocene vs Anthropocene question. Which one of these epochs does human activity fall into? Where and when are the boundaries?

&nbsp;
<h2>Geologic Time</h2>
Before we dive into the debate, we need to understand a few elements of how geologic time gets sorted out. Supereons, eons, eras, epochs, and ages are all progressively smaller units of time. The smaller units fit into the bigger units, almost like a Russian nesting doll. The bigger units of time - like the eons - are very long. For example, our current eon, the Phanerozoic eon, started about 541 million years ago (mya) and stretches until now. For comparison, our current age, the Meghalayan age, only started 4,200 years ago and stretches until today. The Holocene vs Anthropocene debate exists on the level of epochs. Reference the chart below to get a better idea of what we’re talking about.

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<img class="alignnone size-large wp-image-1876356" src="https://www.earth.com/wp-content/uploads/2019/08/image-495x1024.png" alt="" width="495" height="1024" />

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The Proterozoic and Archaean eons are smaller divisions of time within the Precambrian supereon. As you move further right in the chart, we see the smaller division of periods and ages. 

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<h2>Barriers and Divisions</h2>
Each of these time periods contains characteristic events that occurred during them. These relate to both geologic changes as well as changes to life on earth. For example, the Cambrian period is defined by a major event called the <a href="https://www.earth.com/news/cambrian-explosion-fossil-sponges/" target="_blank" rel="noopener noreferrer">Cambrian Explosion</a>. This involved a rapid diversification of life on earth. The vast majority of phyla (a level of biological classification that is smaller than a kingdom, but larger than a class) that presently exist on earth evolved during this period. Never before seen organisms were appearing on earth: worms, sponges, and early chordates all evolved during this period. 

Each of these divisions of geologic time is typically ‘bookended’ by major events on earth. For example, the Oligocene epoch is marked by the start of major antarctic glaciation and the <a href="http://adsabs.harvard.edu/full/1994AREPS..22..145P" target="_blank" rel="noopener noreferrer">Grande Coupure extinction event</a>. Additionally, specific geologic strata - or layers - are used to indicate each of the time periods. Deciding about the exact location (and existence) of the Anthropocene and Holocene border has proven to be contentious. 

&nbsp;
<h2>Holocene</h2>
The currently accepted epoch that we exist in today is called the Holocene (roughly translated as ‘entirely recent’). It began approximately 11,650 years ago with the ending of the <a href="https://science.sciencemag.org/content/325/5941/710" target="_blank" rel="noopener noreferrer">Last Glacial Maximum</a>, with an event known as the Holocene glacial retreat. This glacial retreat scarred the earth in ways that we still see today. For example, the lakes in Minnesota and Wisconsin, and the remnants of glaciers in Colorado and Washington are all remnants of this period. 

The Holocene also coincides with the effects of modern humans on planet earth. This includes the agricultural revolution and every known major civilization in human history. The Holocene is further divided into three Ages: Greenlandian, Northgrippian, and Meghalayan. 

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<h2><img class="alignnone size-large wp-image-1876358" src="https://www.earth.com/wp-content/uploads/2019/08/smoke-258786_1920-1024x663.jpg" alt="human pollution" width="1024" height="663" /></h2>
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<h2>Anthropocene</h2>
More recently, some scientists have been advocating for the creation of a new epoch: the Anthropocene. The term was coined by Nobel laureate Paul Crutzen in the early 2000s and is derived from the Greek ‘anthropo’ for human, and ‘cene’ for new. Scientists argue that humans have had such an impact on the earth - <a href="https://www.theguardian.com/environment/2017/jul/10/earths-sixth-mass-extinction-event-already-underway-scientists-warn" target="_blank" rel="noopener noreferrer">the 6th mass extinction</a>, <a href="https://www.smithsonianmag.com/science-nature/scientists-anthropocene-officially-thing-180957742/" target="_blank" rel="noopener noreferrer">the development of atomic technologies</a>, <a href="https://climate.nasa.gov/scientific-consensus/" target="_blank" rel="noopener noreferrer">and the advent of global climate change</a> - that we need a new epoch after the Holocene. This would be the first new epoch boundary to occur while humans have been on planet earth. It would effectively add a third epoch to the Quaternary period.

&nbsp;
<h2>Holocene vs Anthropocene Debate</h2>
The debate doesn’t really center around which epoch we are currently in, but more so on the existence of the Anthropocene, and our ability to distinguish it. While the effects on the natural world by human activity in the last ~150 years are undeniable, experts are more skeptical on the geological record. “When you start naming geologic-time terms, you need to define what exactly the boundary is, where it appears in the rock strata,” <a href="https://www.smithsonianmag.com/science-nature/what-is-the-anthropocene-and-are-we-in-it-164801414/" target="_blank" rel="noopener noreferrer">says stratigrapher</a> Whitney Autin of the SUNY College of Brockport. This boundary could possibly be defined by the presence of radioactive particles in the soil around the world, a ubiquitous phenomena observed after events World War Two and the <a href="https://www.earth.com/news/vacations-hell-chernobyl/" target="_blank" rel="noopener noreferrer">Chernobyl Nuclear Disaster</a>.

Defining the Anthropocene and cementing human activity into the geological record may also help send a message to the public. “[It] will be another strong reminder to the general public that we are now having undeniable impacts on the environment at the scale of the planet as a whole, so much so that a new geological epoch has begun” says Will Steffen, who heads Australia National University’s Climate Change Institute.

Regardless of what the scientific consensus ends up being, one fact is strikingly obvious: humans are altering planet earth. Consider <a href="https://www.earth.com/take-action-save-earth/" target="_blank" rel="noopener noreferrer">taking action</a> to support organizations that fight against global climate change and the effects it will have on all of us.

&nbsp;

Holocene vs Anthropocene Debate

The earth is very very old. About 4.5 billion years...

Dunes sagebrush lizard

<div itemprop="video" itemscope itemtype="http://schema.org/VideoObject"><div id="58e3ebce955a315103d39bd1" class="vdb_player vdb_58e3ebce955a315103d39bd158d96b98cd4fed198a0d2a49" > <script type="text/javascript" src="https://delivery.vidible.tv/jsonp/pid=58e3ebce955a315103d39bd1/vid=5c5a0e924deb1a5e3b5bcff6/58d96b98cd4fed198a0d2a49.js?"></script></div> <meta itemprop="name"content="Are there cases of convergent evolution between reptiles and amphibians?" /> <meta itemprop="duration" content="T7M4S" /> <meta itemprop="thumbnailUrl" content="https://img.vidible.tv/prod/2019-02/05/5c5a0e924deb1a5e3b5bcff6/5c5a12bd9d15d700019abba8_1280x720_FES_v1.jpg" /> <meta itemprop="embedUrl" content="https://delivery.vidible.tv/htmlembed/pid=58e3ebce955a315103d39bd1/58d96b98cd4fed198a0d2a49.html?vid=5c5a0e924deb1a5e3b5bcff6" /> <meta itemprop="uploadDate" content="2019-02-05T22:30:42Z" /> <meta itemprop="expires" content="" /> <meta itemprop="description" content="" /> <meta itemprop="height" content="720" /> <meta itemprop="width" content="1,280" /></div>
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It’s easy to see that lizards and salamanders have similarities. Their bones and basic body structure are remarkably similar. A major difference between the true groups of herptiles is, of course, skin the lizards are scaly while the salamander’s skin is smooth and porous. These differences are obvious reflections of different lineages, those of amphibians and reptiles respectively. It’s clear that the evolutionary history of salamanders and lizards is very different from the outset.

Interestingly, the evolution of a similar body plan in lizards and salamanders doesn’t quite qualify as convergent evolution, one of the more interesting ideas in evolutionary theory. Convergent evolution is the adaptation of two different types of animals to a similar habitat or niche.

It’s probably obvious that salamanders and lizards live very different lives. Salamanders require water for at least part of their lives, while some species never leave the water at all. Lizards, on the other hand, are sometimes adapted to dry conditions as anyone who has spent time hiking in the desert of Utah can attest to. Some lizards have as far as evolving to never drink water, obtaining all their hydration from prey instead. Clearly, the tailed quadrupedal body of both lizards and salamanders simply evolved for two separate types of life, not due to similar evolutionary pressures. There are still some interesting cases of convergent evolution between reptiles and amphibians.

One type of salamander does actually resemble a specific type of lizard in what can be considered convergent evolution of tongues. The Plethodontidae family of salamanders often referred to simply as the ‘lungless’ salamanders may seem at first blush nothing like chameleons. However, as a paper in the Journal of Experimental Biology notes, some of these salamanders have extremely high powered tongue projection.

The tongue of these salamanders can be extended up to 80% of the animal’s total body length in just 20 milliseconds. If you’ve ever observed chameleons for any length of time, you’ll have noticed that they too have projectile tongues used to capture elusive prey. According to National Geographic, chameleon tongues average even longer at about twice the animal’s normal body length. Not just tongues have converged in their evolution in reptiles and amphibians.

Prionosuchus is an extinct genus of amphibians that lived in what is now Brazil approximately 270 million years ago. Brazil in the Permian when Prionosuchus lived wasn’t radically different from what we think of Brazil today: hot, humid and forested. The amphibian was found with fish and other aquatic animals, so it certainly lived in the water like its extant relatives.

According to NewDinosaurs, Prionosuchus was a giant, measuring up to 30 feet long and weighing more than 2 tons when alive. Most specimens are much smaller but the larger individuals would have been terrifying. The monstrous amphibian also had a long, thin snout lined with sharp teeth and a low, squat body with a wide tail adapted for swimming. Interestingly, with its general body shape, aquatic lifestyle, and tropical habitat, Prionosuchus resembles nothing so much as an extinct, amphibian crocodilian. Indeed, it seems likely that Prionosuchus once inhabited the same ecological niche now occupied by crocodiles and alligators. Other examples of convergence are out there.

Much has been made about the convergent evolution of flight and it is fascinating. Birds, bats, pterosaurs, and insects are not closely related but all have evolved the ability to fly. It’s obvious with not much more than a cursory examination that the ways in which each of these animals fly are unique to their lineage. An insect wing is nothing like the boney feathered wing of an eagle and neither is very much like the membrane spread over a modified hand that bats use to fly. There is convergent evolution not just in flying but also in gliding.

So-called flying squirrels are probably the most famous example of animals that regularly glide. Mammals aren’t the only animals to evolve the ability to glide though, and much like the art of flight, it has evolved differently among different animals. With flying squirrels, there is a membrane of skin between the limbs which allows the animal to glide.

The Malabar Gliding Frog (Rhacophorus malabaricus) evolved a different strategy. The gliding frog is native to the Western Ghats, a mountain range in India where it lives a life in trees. The frog can extend its large webbed feet when jumping and glide. Another tree frog, the genus Ecnomiohyla of Central and South America evolved to glide in the same way, an example of convergent evolution among different frog groups. The lizard genus Draco has evolved a remarkably similar strategy to a similar problem though in a very different way.

Draco has a flattened rib cage which can expand beyond their normal configuration reports National Geographic. With ribs extended, skin is stretched across them, making the lizard appear superficially like a flying squirrel. Interestingly, Draco is also found in the forests of Southeast Asia, where the female lizards only venture down from the trees to lay their eggs on the ground. The ability to glide is a useful one for quickly escaping predators or perhaps even catching prey.

There’s even a genus of snakes, Chrysopelea that evolved the ability to glide by flattening their bodies and undulating in a unique way. These snakes are also native to the forests of Southeast Asia, a place that seems to be a hotspot for the evolution of gliding. Southeast Asia is even the home to two genera of gliding geckos. Clearly there must have been a lot of danger lurking in the heights of Asia’s forests that gave an advantage to those animals that could leap away and glide to safety. Or perhaps the ability to glide is an adaptation to being prone to falling. Either way, patterns that show up again and again in unrelated organisms tell us something important.

Convergent evolution shows us the extent to which the same physical limitations dictate our individual histories. Each lineage may respond differently but sometimes it’s a response to the same problem, similar in effect to different engineers contriving unique solutions to the same problem. The difference, of course, is that evolution is a natural process occurring without guidance over vast stretches of time acting on minute difference in genetics.

Are There Cases of Convergent Evolution Between Reptiles and Amphibians?

&nbsp; It’s easy to see that lizards and salamanders have...

With eight legs, multiple eyes, and fangs that can inject venom, spiders are a terrifying sight for some. Despite their menacing appearance, these little critters are important components to every ecosystem they’re found in. Many people refer to spiders and other creepy-crawly things as insects. They do have lots in common with insects, and they even look and behave a lot like our six-legged friends. But, are spiders insects?

Technically speaking, spiders are not insects! Why aren’t they exactly? We’ll look into a few main reasons why spiders and insects are so different. But first, let’s break down what spiders and insects have in common, which is actually quite a bit.

To understand the similarities and differences between spiders and insects, we have to cover a bit of taxonomy. Taxonomy is the science of <a href="https://www.earth.com/news/humans-classify-life-taxonomy/" target="_blank" rel="noopener noreferrer">classifying all living things</a>. Spiders, insects, fish, birds, and humans all fall into the Kingdom Animalia. Pretty much every animal is able to breathe and move, unlike plants and fungi. Additionally, animals are multicellular, unlike bacteria. Let’s dive deeper into the world of taxonomy and discover more about the classification of spiders and insects.

[caption id="attachment_1875952" align="alignnone" width="1024"]<img class="wp-image-1875952 size-full" src="https://www.earth.com/wp-content/uploads/2019/08/jumping-spider-feeding-on-fruitfly-jeff-burcher-flicker-1024x819.jpg" alt="are spiders insects, jumping spider" width="1024" height="819" /> Photo by Jeff Burcher[/caption]
<h2>Spiders and Insects Are Arthropods</h2>
Getting more specific, we move into the Phylum of Arthropoda. Spiders and insects are still together in this group, as are crustaceans, centipedes, and the <a href="https://www.fossilera.com/pages/about-trilobites" target="_blank" rel="noopener noreferrer">famous extinct Trilobite</a>. Arthropods are an incredibly successful group of animals and can thrive in the deep ocean, wet forests, and extremely hot deserts. But what makes an arthropod an arthropod?

First of all, arthropods are invertebrates. Unlike mammals, birds, and reptiles, they lack a spinal column. Instead, arthropods have super hard exoskeletons on the outside of their body, made up of stuff called chitin. Chitin is actually very similar to the material that makes up our very own hair and fingernails! In order to grow, an arthropod must shed its exoskeleton and create a new one. <a href="https://www.youtube.com/watch?v=Bw1MFdlmWyA" target="_blank" rel="noopener noreferrer">Here's an awesome video</a> of a cicada shedding its exoskeleton.

Another defining characteristic of an arthropod is having segmented legs. In fact, that’s exactly where the name arthropod comes from. Arthro means jointed, and pod means leg. There are a few other more technical characteristics of arthropods, but we won’t worry about those.

[caption id="attachment_1875950" align="alignnone" width="1300"]<img class="wp-image-1875950 size-full" src="https://www.earth.com/wp-content/uploads/2019/08/Spider-characteristics.png" alt="Are spiders insects, Spider anatomy" width="1300" height="996" /> (1) Four pairs of legs, (2) cephalothorax, and (3) abdomen[/caption]
<h2>Spiders Are Not Insects!</h2>
The next taxonomic level down is where spiders and insects lose their similarities. Spiders are in a class of animals known as arachnids. Spiders, scorpions, mites, and ticks are all <a href="https://www.earth.com/news/arachnids-spiders-scorpions/" target="_blank" rel="noopener noreferrer">different kinds of arachnids</a>. Perhaps the biggest difference between arachnids and insects are the number of legs they have. One of the defining characteristics of spiders and other arachnids is that they have 8 legs. Insects, on the other hand, only have 6. This difference may not seem that significant, but it’s one of the most important things that separate these two classes of animals!

Next up is the number of body segments. Spiders have two segments - the abdomen, and the cephalothorax (which is a combination of a head and thorax). Insects boast three distinct segments - an abdomen, a thorax, and a head. Although they serve essentially the same functions, the body segments are another characteristic that spiders and insects do not have in common.

On the topic of body parts, insects have developed <a href="https://www.si.edu/spotlight/buginfo/insect-flight" target="_blank" rel="noopener noreferrer">wings for flight</a>. Nearly all insect species are capable of flight - even ants, although it’s usually just the queen who's able to. Spiders and other arachnids are not able to fly. Which is good for us, because if they could, they would be about a thousand times scarier.

<img class="alignnone wp-image-1875954 size-full" src="https://www.earth.com/wp-content/uploads/2019/08/golden-orb-spider-281142_1280.jpg" alt="Are spiders insects, golden orb weaver" width="1280" height="851" />

Of course, the differences between spiders and insects don't stop there. They have very different roles in their ecosystems as well. Mainly, spiders are carnivores and hunt for their food, usually by using webs made of silk. Many insects (<a href="https://www.mnn.com/your-home/organic-farming-gardening/stories/7-things-you-never-knew-about-dragonflies" target="_blank" rel="noopener noreferrer">but not all of them!</a>) are herbivores and are often a tasty snack for other animals, including spiders.

So, now you know! Contrary to what many people believe, spiders are not insects. We’ll leave you with this super cool video of a <a href="https://www.earth.com/news/peacock-spiders-mating-displays/" target="_blank" rel="noopener noreferrer">peacock spider</a> dancing to attract a mate.

[embed]https://www.youtube.com/watch?v=d_yYC5r8xMI[/embed]

Are Spiders Insects?

With eight legs, multiple eyes, and fangs that can inject...

Humans and bacteria have coexisted for millions of years. Many of these microbes are necessary to our lives on earth. For example, the bacteria Lactobacillus acidophilus aids in the digestion of food <a href="https://www.earth.com/news/gut-microbiome-promotes-healthier-aging/">in our gut.</a> Streptococcus thermophilus is a starting culture for yogurt and some cheese. While these bacteria are helpful, others, known as pathogenic, are capable of causing disease. What are some of the most deadly diseases caused by bacteria? First, let’s understand more about microbes. 
<h2>What are Bacteria?</h2>
<a href="https://www.earth.com/earthpedia-articles/the-strange-shapes-of-bacteria/" target="_blank" rel="noopener noreferrer">Bacteria</a> are <a href="https://www.biology.iupui.edu/biocourses/N100/2k23domain.html" target="_blank" rel="noopener noreferrer">one of the three domains of life</a> - along with eukarya and archaea. They are characterized by several key features:
<ul>
 	<li style="font-weight: 400;">Single-cell: all bacteria are single-celled organisms. This means that each cell must be capable of accomplishing every function that an entire multi-celled organism is capable of. </li>
 	<li style="font-weight: 400;">Size: bacteria are much smaller than human cells. A typical bacterial cell is the same size as a human mitochondrion. This is about ten times smaller than a typical human cell.</li>
 	<li style="font-weight: 400;">Organelles: Human cells have a whole host of membrane-bound organelles, including nuclei and lysosomes. Bacterial cells, on the other hand, have no membrane-bound organelles. </li>
</ul>
<h2><img class="alignnone wp-image-1875760 size-full" src="https://www.earth.com/wp-content/uploads/2019/07/bacteria-62993_1280.jpg" alt="diseases caused by bacteria cluster" width="1280" height="930" /></h2>
<h2>How Bacteria Make Us Sick</h2>
The first phase of sickness from a bacterial infection isn’t the bacteria itself. Instead, it is <a href="http://needtoknow.nas.edu/id/infection/how-pathogens-make-us-sick/" target="_blank" rel="noopener noreferrer">our body’s response to the bacteria</a>. Our immune system recognizes that there is an invader and attempts to get rid of the foreign bacteria. Many of the initial symptoms - fever, rash, headache - are simply our innate immune response to infection. 

Some of the most deadly diseases are caused by the actual effects of the bacteria. These can manifest themselves in many different ways. For example, some bacteria multiply so quickly that they crowd our tissues and organs. This often disrupts normal functions or stops them entirely. Others release toxins that can damage cells and disrupt immune responses. Consequently, while the effects of pathogenic bacteria vary widely from species to species, the effects are always negative. 
<h2>Deadly Diseases</h2>
Now that we understand what bacteria are and how they cause disease, let’s take a look at some of the most deadly diseases caused by microbes. 
<h3>Bubonic Plague</h3>
The term ‘plague’ is oftentimes used to describe any disease outbreak. While it is commonly used to describe any disease that is especially nasty, this is incorrect. In fact, a <a href="https://www.mayoclinic.org/diseases-conditions/plague/symptoms-causes/syc-20351291" target="_blank" rel="noopener noreferrer">plague</a> is a specific disease caused by the bacterium, and it has three variations. The first variation is one that appears in history books: the bubonic plague. This version of plague infects the lymph nodes, causing them to swell. This triggers an immune reaction causing the victim to experience flu-like symptoms. 

The bubonic plague pandemic of the 14th century was the most devastating disease outbreak in recorded human history. Y. pestis is estimated to have killed a third of Europe’s population at the time - <a href="https://www.nationalgeographic.com/science/health-and-human-body/human-diseases/the-plague/" target="_blank" rel="noopener noreferrer">roughly 25 million people</a>. However, even with modern medicine the bubonic plague still has a mortality rate of 10%. Most of these reported cases originate in Africa. 
<h3>Anthrax</h3>
In popular culture, anthrax manifests itself in the form of a white powder that can cause disease. In reality, anthrax is the disease caused by the bacterium Bacillus anthracis, and it causes a whole host of nasty problems. B. anthracis originates in soil, plants, and water, but it is usually transmitted to humans via infected livestock like cattle or sheep. 

Symptoms of anthrax are <a href="https://www.cdc.gov/anthrax/basics/symptoms.html" target="_blank" rel="noopener noreferrer">similar to symptoms of the worst flu</a>. An infected individual may experience nausea, vomiting, sweats, confusion, diarrhea, and blisters or small bumps on the skin. Serious cases of exposure require hospitalization, often requiring aggressive treatment of ventilation and fluid drainage. Left untreated, the bacteria will produce toxins that can be deadly to humans.
<h3>Botulism</h3>
Botulism is usually caused by the bacterium Clostridium botulinum. It can be the result of improperly stored foods - like home-made canned goods. The symptoms of botulism can appear extremely rapidly - <a href="https://www.cdc.gov/botulism/symptoms.html" target="_blank" rel="noopener noreferrer">sometimes as soon as six hours post-infection</a>. If those symptoms do manifest, they are not fun. 

First, victims will have a hard time controlling their minor muscle movements. For example,  they may struggle to open their eyes, swallow, breath, and experience generalized weakness. All of these symptoms are the result of the chief problem with botulism: paralysis. The toxins released by C. botulinum cause paralysis, which, if left untreated, can stop the victim’s breathing eventually causing death. 
<h3><img class="alignnone wp-image-1875758 size-full" style="font-size: 16px;" src="https://www.earth.com/wp-content/uploads/2019/07/pill-1884775_1920.jpg" alt="diseases caused by bacteria pills and antiobiotics " width="1920" height="1152" /></h3>
<h2>Disease Cures</h2>
Each of these diseases can, in theory, be treated with the proper course of antibiotics. The rise of antibiotic-resistant strains of various bacteria has complicated this option. This increase is directly related to an increase in the prescription of antibiotics. In 2015 alone, Clostridioides difficile killed<a href="https://www.cdc.gov/botulism/testing-treatment.html" target="_blank" rel="noopener noreferrer"> 15,000 people</a> due to a lack of effective antibiotics. In the future, we will have to develop new and innovative means of treating these deadly diseases. 

&nbsp;

&nbsp;

Most Deadly Diseases Caused by Bacteria

Humans and bacteria have coexisted for millions of years. Many...

The History of Earth in Exactly 2000 Words

The history of Earth is obviously a ginormous topic. Really,...

Many of us interact with bacteria on a daily basis. If you eat yogurt or cheese you can thank bacteria! They are so common that there are <a href="https://www.nature.com/news/scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136" target="_blank" rel="noopener noreferrer">about as many bacterial cells</a> as human cells in your body. Their diversity is also stunning. Recent estimates found that there are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3160642/" target="_blank" rel="noopener noreferrer">over one billion</a> different types of bacterial species. Even though bacteria may seem wildly different than humans, we all do have at least one thing in common: we all undergo reproduction. Bacteria definitely don't reproduce like humans or other animals, so exactly how do bacteria reproduce?
<h1>Domains of Life</h1>
Before we talk about how bacteria reproduce, we need to understand their place in biology. All life on earth evolved about 3.5 billion years ago. Scientists think we all <a href="https://www.nationalgeographic.com/news/2010/5/100513-science-evolution-darwin-single-ancestor/#close" target="_blank" rel="noopener noreferrer">came from one common ancestor</a>. Since then, living organisms have changed greatly. The first way to distinguish one organism from another is by classifying what domain it falls into. 

Current classification uses three domains: eukarya, archaea, and bacteria. Bacteria are then grouped into five major categories: proteobacteria, cyanobacteria, chlamydiae, spirochetes, and firmicutes.
<h1>Bacterial Uses</h1>
Bacteria are all around us. From our bodies to our food. From the <a href="https://askabiologist.asu.edu/explore/desert-microbes" target="_blank" rel="noopener noreferrer">hottest deserts</a> to the <a href="https://blogs.ei.columbia.edu/2010/01/26/tundra-microbes-and-world-climate/" target="_blank" rel="noopener noreferrer">coldest tundras</a>. Between the <a href="https://link.springer.com/article/10.1007/s11434-007-0360-4" target="_blank" rel="noopener noreferrer">highest mountains</a> to the <a href="https://divediscover.whoi.edu/hot-topics/bacteria-at-hydrothermal-vents/" target="_blank" rel="noopener noreferrer">deepest oceans</a>, bacteria live everywhere. Over the last several thousand years, we humans have learned to use bacteria to our benefit. 

Let’s take a look at some of the unique ways we use bacteria.
<h2>Cheese</h2>
Cheesemaking brings together everybody’s favorite ingredients: milk, salt, and bacteria. A necessary step in almost all cheese production is the separation of the two products of curdling: curds and whey. This process is accomplished by acidifying the pre-cheese mixture. While this can be accomplished by adding acid directly, more often, various types of <a href="https://www.sciencedirect.com/science/article/pii/B9780750615136500111" target="_blank" rel="noopener noreferrer">starter cultures</a> are used. 

The starter bacteria accomplish two things. First, they digest the milk sugars and turn them into lactic acid. Second, they help to develop the flavor protein of the cheese. Different bacteria are used for different cheeses. Interestingly, certain strains of bacteria even help to give some cheese their <a href="https://www.earth.com/video/what-makes-some-cheese-smell-so-bad/">awful smell</a>.
<h2><img class="alignnone wp-image-1878671 size-large" src="https://www.earth.com/wp-content/uploads/2019/11/compost-419261_1280-1024x682.jpg" alt="compost garden" width="1024" height="682" /></h2>
<h2>Composting</h2>
Composting is a method of using bacteria and air to break down organic solids. In other words, it can be an <a href="https://www.earth.com/news/composting-eco-friendly-decisions/">easy, at-home</a> way to sustainably get rid of your food waste. Typically, it will involve a large, covered container that stores the waste. First, it needs to be placed in the sun and given the room to ventilate. After that, the composter becomes the perfect home for billions of bacteria. 

The bacteria come from many places. Whereas some come from the surfaces of the waste or our hands, others exist in the ambient environment. They slowly break down the scraps and waste into organic fertilizer. Alternatively, it can now be safely disposed of in a much more environmentally friendly manner.
<h2>Bioremediation</h2>
Bioremediation is the process of using living organisms to <a href="https://www.intechopen.com/books/advances-in-bioremediation-of-wastewater-and-polluted-soil/bioremediation-of-polluted-waters-using-microorganisms" target="_blank" rel="noopener noreferrer">clean up a polluted area</a>. Bacteria are capable of utilizing dangerous heavy metals, like lead, and transforming them into other compounds that are no longer dangerous. 

What's more, recent studies have made significant headway into showing the possible uses of bioremediation technology. Scientists are hopeful that these processes can help with mining accidents and even <a href="https://www.scientificamerican.com/article/how-microbes-clean-up-oil-spills/" target="_blank" rel="noopener noreferrer">oil spills</a>.

<img class="alignnone size-large wp-image-1878670" src="https://www.earth.com/wp-content/uploads/2019/11/bacteria-808158_1280-1024x731.jpg" alt="bacteria" width="1024" height="731" />
<h1>Reproduction</h1>
Now that we understand where bacteria fit and what they’re used for, let’s take a look at how they reproduce.
<h2>Binary Fission</h2>
The most common way for bacteria to reproduce is through binary fission. The basics of the process are simple. First, the cell grows to approximately double its normal size. Next, it makes a copy of all of its genetic material. This is through a process called DNA replication. Last, the cell actually splits down the middle into two identical ‘daughter’ cells. This process is roughly the same as how our body cells reproduce. 

Specifically, binary fission is a type of asexual reproduction because there is no exchange of genetic material at the time of the split.
<h2>Baeocyte Production</h2>
Baeocyte production is very different from binary fission. Contrary to binary fission which copies genetic information once, some types of bacteria will copy their DNA dozens and dozens of times. After the copying is complete, the ‘parent’ cell will rapidly divide dozens or hundreds of times. As a result, dozens or even hundreds of new baeocytes form. This is a common process found in <a href="https://link.springer.com/article/10.1007/BF01283581">cyanobacteria</a>.
<h2>Budding</h2>
Budding is a reproductive strategy that is more commonly seen in eukaryotic single-celled organisms, like yeast. Essentially, the bacteria stretch out into large, thin cells with a set of ‘arms’ around the center. Each of these arms is the site of a ‘budding’ event, whereby new buds can break off. 

Each of these buds can go on to be a fully functioning adult bacteria. These bacteria, themselves, will undergo budding. While less common, this process takes place for many different bacteria across the whole domain of bacteria. Indeed, you can find the process of budding in almost all major types of bacteria.
<h1>Wide World of Bacteria</h1>
We’ve now seen that bacteria can live almost anywhere, and their diversity of uses is paralleled by their unique strategies of reproduction. Next time you’re eating a cultured food think about the fact that bacteria helped create it!

Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

How Do Bacteria Reproduce

Many of us interact with bacteria on a daily basis....

<figure class="wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio"><div class="wp-block-embed__wrapper">
https://www.youtube.com/watch?v=2E0mn5mTvhQ
</div><figcaption class="wp-element-caption">'Death Star' moon Mimas conceals a 15-million-year-old ocean that scientists never expected.</figcaption></figure>



<h2 class="wp-block-heading" id="h-hidden-waters-beneath-ancient-craters">Hidden waters beneath ancient craters</h2>



Scientists have made a startling discovery that challenges everything we thought we knew about <a href="https://www.earth.com/news/saturn-moon-mimas-has-remarkably-young-ocean/" target="_blank" rel="noreferrer noopener">Saturn's moon Mimas</a>. Beneath the heavily cratered surface that earned it the nickname "Death Star" lies a global ocean that formed just 5 to 15 million years ago—a remarkably young age by cosmic standards.



<h2 class="wp-block-heading" id="h-cassini-data-reveals-orbital-secrets">Cassini data reveals orbital secrets</h2>



The discovery, led by Dr. Valéry Lainey of the <a href="https://observatoiredeparis.psl.eu/" target="_blank" rel="noreferrer noopener">Observatoire de Paris</a>, emerged from careful analysis of <a href="https://www.nasa.gov" target="_blank" rel="noreferrer noopener">NASA</a>'s Cassini spacecraft data. By studying subtle irregularities in Mimas's orbit around Saturn, researchers detected the gravitational signature of liquid water hidden 20 to 30 kilometers beneath the moon's icy shell.



<h2 class="wp-block-heading" id="h-an-unlikely-ocean-world">An unlikely ocean world</h2>



At only 400 kilometers in diameter, Mimas seemed like the least likely candidate to harbor a subsurface ocean. Unlike other ocean moons such as Europa and Enceladus, which show clear surface signs of internal activity, Mimas displays no obvious hints of the liquid water beneath its ancient, crater-scarred exterior.



"Mimas is a small moon, and its heavily cratered surface gave no hint of the hidden ocean beneath," explained Dr. Nick Cooper from <a href="https://www.qmul.ac.uk/" target="_blank" rel="noreferrer noopener">Queen Mary University of London</a>, a study co-author.



<h2 class="wp-block-heading" id="h-implications-for-astrobiology">Implications for astrobiology</h2>



The ocean's recent formation makes Mimas a prime target for studying how oceans develop and potentially support life. This discovery adds another member to the exclusive club of ocean worlds in our solar system, each offering unique insights into the conditions necessary for habitability.



The research, published in <a href="https://www.nature.com/" target="_blank" rel="noreferrer noopener">Nature</a> journal, demonstrates how advanced orbital analysis can reveal hidden features of celestial bodies, opening new possibilities for understanding ocean formation throughout the cosmos.



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Scientists discover unexpected young ocean on Saturn's cratered moon Mimas

https://www.youtube.com/watch?v=2E0mn5mTvhQ 'Death Star' moon Mimas conceals a 15-million-year-old ocean that...

<figure class="wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio"><div class="wp-block-embed__wrapper">
https://www.youtube.com/watch?v=3Y4eLFNYrKE
</div></figure>



On the unforgiving landscape of North Greenland, temperatures drop and sunlight barely penetrates through the polar winter. It was here, however, that an international team of scientists found <a href="https://www.earth.com/news/predatory-worms-were-terror-beasts-half-a-billion-years-ago/#google_vignette" target="_blank" rel="noreferrer noopener">evidence of sea monsters</a> that would change our understanding of ocean life in the past.



This video captures the discovery of Timorebestia fossils that had been hidden for more than 500 million years in the Sirius Passet formation. The "terror beasts," as they are called, are a hidden chapter in the evolutionary history of <a href="https://www.earth.com" target="_blank" rel="noreferrer noopener">Earth</a>, showing that sophisticated predator-prey interactions occurred much earlier than previously envisioned.



Dr. Jakob Vinther and his research team at the <a href="https://www.bristol.ac.uk/" target="_blank" rel="noreferrer noopener">University of Bristol</a>, in collaboration with researchers at the <a href="https://eng.kopri.re.kr/" target="_blank" rel="noreferrer noopener">Korean Polar Research Institute</a>, braved extreme weather conditions at 82.5 north latitude to locate these giant creatures. Using sophisticated electron microprobe analysis, they revealed the detailed anatomy of the animals, including their muscle and nerve tissues.



The find upsets the traditional timeline of sea predators. Although we've long appreciated that Cambrian oceans were at one time ruled by <a href="https://www.youtube.com/watch?v=jWI3-UgA3_o&amp;list=PL1QLQMW9MWDwpkFOnvgAmu7wT6rZmYqdJ&amp;index=19" target="_blank" rel="noreferrer noopener">arthropods</a>, these discoveries indicate that relatives of arrow worms were first to dominate the seas. These worms were building sophisticated food webs several million years before other predator groups arose.



Each fossil is a story of ancient hunger, with fossil stomach contents revealing these meter-long beasts dined on heavily armored arthropods regularly, cementing their place as the ocean's first apex predators.



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Worms dominated seas before dinosaurs

https://www.youtube.com/watch?v=3Y4eLFNYrKE On the unforgiving landscape of North Greenland, temperatures drop...

<figure class="wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio"><div class="wp-block-embed__wrapper">
https://www.youtube.com/watch?v=Ow3JH03PqEQ
</div><figcaption class="wp-element-caption">New York is the site of the world's oldest forest.</figcaption></figure>



<h2 class="wp-block-heading" id="h-385-million-year-old-trees-discovered">385-million-year-old trees discovered</h2>



Scientists have uncovered something extraordinary just two hours north of New York City. The <a href="https://www.earth.com/news/worlds-oldest-forest-discovered-close-to-new-york-city/" target="_blank" rel="noreferrer noopener">world's oldest forest</a>, dating back 385 million years, offers a window into how Earth's first complex forests shaped our planet's atmosphere.



Located near <a href="https://townofcairo.com/" target="_blank" rel="noreferrer noopener">Cairo, New York</a>, in Greene County, these weren't merely primitive plants struggling to survive. These were sophisticated trees with root systems remarkably similar to modern forests. This ancient woodland predates dinosaurs by 140 million years.



<h2 class="wp-block-heading" id="h-the-cairo-forest-discovery">The Cairo forest discovery</h2>



385 million years ago, upstate New York was a tropical paradise near the equator. Thanks to continental drift, this ancient forest has traveled thousands of miles to its current location.



The fossil forest sits in an abandoned quarry, roughly half the size of a football field. This represents just a slice of what was likely a massive forest system stretching from New York into Pennsylvania.



Charles Ver Straeten, curator of sedimentary rocks at the <a href="https://www.nysm.nysed.gov/" target="_blank" rel="noreferrer noopener">New York State Museum</a>, made the discovery in 2009. While scouting the former highway department property, his trained eye spotted wandering patterns in the stone that looked like marine features.



<h2 class="wp-block-heading" id="h-revolutionary-age-and-preservation">Revolutionary age and preservation</h2>



The site contains 385-million-year-old rocks with fossilized woody roots forming horizontal patterns up to 18 feet (5.5 meters) wide. As Christopher Berry, a paleobotanist at Cardiff University, explains: "You are walking through the roots of ancient trees."



This discovery pushes back advanced tree evolution by millions of years. The research, published in <a href="https://www.cell.com/current-biology/home" target="_blank" rel="noreferrer noopener">Current Biology</a> in December 2019, fundamentally changes our understanding of when complex forests first emerged.



Researchers believe a massive flood buried the forest floor, creating perfect fossilization conditions. Over millions of years, sediment hardened into rock, preserving these root patterns like nature's time capsule.



<h2 class="wp-block-heading" id="h-meet-archaeopteris-the-first-modern-tree">Meet Archaeopteris: the first modern tree</h2>



The star of this ancient forest is Archaeopteris – not to be confused with the feathered dinosaur Archaeopteryx. This tree was far older and more revolutionary.



William Stein from <a href="https://www.binghamton.edu/" target="_blank" rel="noreferrer noopener">Binghamton University</a> describes the roots as "strikingly modern, essentially what you'd see outside in my yard right now." These weren't simple root systems you'd expect from ancient plants.



Some fossilized roots are six inches (15 centimeters) in diameter, forming 36-foot-wide (11-meter) patterns. These giants grew up to 65 feet (20 meters) tall with five-foot-diameter (1.5-meter) trunks.



<h2 class="wp-block-heading" id="h-climate-changing-impact">Climate-changing impact</h2>



These trees fundamentally changed Earth's environment. Kevin Boyce, a Stanford University geoscientist, explains how their deep roots triggered "weathering," chemical reactions that pulled carbon dioxide from the atmosphere.



This process dropped atmospheric CO2 levels from 10-15 times higher than today to roughly modern concentrations. These ancient trees helped create atmospheric conditions that made complex life possible.



<h2 class="wp-block-heading" id="h-ancient-forest-ecosystem">Ancient forest ecosystem</h2>



The forest was remarkably diverse. Scientists identified Eospermatopteris, palm tree-like plants with short roots that reached 30 feet (9 meters) tall but lacked woody structure. The forest also housed cladoxylopsids and a mysterious third species still being studied.



All reproduced through spores rather than seeds – millions of years before seeds evolved. This tropical environment had no grass, flowers, or flying insects, just towering trees creating Earth's first complex forest canopy.



<h2 class="wp-block-heading" id="h-scientific-significance">Scientific significance</h2>



Before this finding, the Gilboa forest, located 25 miles (40 kilometers) away, held the "oldest forest" title. Cairo's trees are 2-3 million years older, showing that complex forest ecosystems developed much faster than scientists believed possible.



Patricia Gensel, a <a href="https://www.unc.edu/" target="_blank" rel="noreferrer noopener">University of North Carolina</a> paleobotanist, notes: "The size of those root systems is really changing the picture. Even 20 years ago, researchers assumed trees with such complex root systems didn't evolve so early."



The Cairo site presents three unique root systems, suggesting Devonian period forests were diverse ecosystems with different trees occupying different environmental niches, much like today's forests.



<h2 class="wp-block-heading" id="h-modern-preservation-efforts">Modern preservation efforts</h2>



In 2022, New York State Senator Michelle Hinchey secured a $170,000 grant for the town of Cairo to construct specialized fencing around the fossil forest site. The town plans to conduct a feasibility study exploring the possibility of creating an educational center and working lab on-site.



Joe Hasenkopf, chair of the Cairo Planning Board, hopes to partner with educational institutions to create a research facility serving scientists, students, and the public.



<h2 class="wp-block-heading" id="h-lessons-for-today-s-climate">Lessons for today's climate</h2>



Why does a 385-million-year-old forest matter today? It shows how dramatically forests can change Earth's climate. These ancient woodlands created the atmospheric conditions supporting complex life.



Understanding how prehistoric forests transformed the planet helps us appreciate modern forests' critical role in addressing climate change. Forests remain Earth's most effective carbon capture systems.



These prehistoric trees changed Earth's atmosphere by pulling massive amounts of carbon dioxide from the air. As we face modern climate challenges, this ancient forest reminds us of trees' incredible power to transform our planet's environment.



The next time you walk through a forest, remember you're experiencing an ecosystem whose blueprint was established 385 million years ago in upstate New York. These ancient pioneers didn't just survive – they thrived and changed the world forever.



The full study was published in the journal Current Biology.



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Earth's oldest forest found in the United States

https://www.youtube.com/watch?v=Ow3JH03PqEQ New York is the site of the world's oldest...

<figure class="wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio"><div class="wp-block-embed__wrapper">
https://www.youtube.com/watch?v=prrq8Ql81zk
</div><figcaption class="wp-element-caption">Acid rain and a crisis solved.</figcaption></figure>



<h2 class="wp-block-heading" id="h-why-don-t-we-ever-hear-about-acid-rain-anymore-the-environmental-crisis-that-was-solved">Why don't we ever hear about "acid rain" anymore? The environmental crisis that was solved</h2>



Remember the 1980s when acid rain dominated headlines? Dire warnings about rain eating buildings, killing fish, and destroying forests filled every news cycle. Then, almost like magic, acid rain vanished from public discourse. What happened? Did we actually solve one of the late 20th century's most pressing environmental challenges?



The answer might surprise you. Unlike many environmental issues that drag on indefinitely, acid rain represents one of modern history's most successful ecological recovery stories. It's a tale of science, politics, and technology working together to tackle what seemed impossible.



<h2 class="wp-block-heading">What was acid rain?</h2>



Acid rain isn't regular rain having a bad day – it's precipitation that became significantly more acidic due to air pollution. When power plants, factories, and vehicles burn fossil fuels, they release sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere.



<h2 class="wp-block-heading">The science behind it</h2>



Think of acid rain as nature's chemistry experiment gone wrong. These compounds react with water, oxygen, and other chemicals to form sulfuric and nitric acids. When mixed with water vapor in clouds, they create precipitation with dangerously low pH levels.



While clean rain has a pH of about 5.6, acid rain could drop as low as 4.2 to 4.4 – roughly as acidic as tomato juice or coffee. According to US Geological Survey documentation, Scottish chemist Angus Smith first coined "acid rain" in 1872, but it didn't become a household phrase until the 1960s and 1970s when Swedish scientist Svante Odén documented its devastating effects on Scandinavian lakes and European forests.



<h2 class="wp-block-heading">The crisis at its peak</h2>



During the height of public concern, environmental damage was both widespread and visible. This wasn't some abstract future threat – people could see destruction happening in real-time.



<h2 class="wp-block-heading">Environmental devastation</h2>



The most dramatic impacts were impossible to ignore. Research documented by the Adirondack Lakes Survey Corporation and the New York State Department of Environmental Conservation shows that in the Adirondack Mountains, more than 200 lakes became so acidic they couldn't support fish life. The Adirondack Council reports that 409 lakes once supported brook trout, but many lost their fish populations due to acid rain.



By 1976, when scientists cataloged all acidified lakes in the Adirondack Park, researchers found that half of the lakes over 2,000 feet above sea level had no fish, according to studies published in environmental journals. The acidification process worked like a slow-motion disaster. As acid rain fell into watersheds, it gradually lowered pH levels. Fish couldn't survive in acidic water, and their food sources died off too.



Trees at high elevations showed stress directly linked to acid rain. It weakened them by leaching nutrients and making them susceptible to disease. Historical records show Germany's Black Forest saw nearly half its trees damaged by the mid-1980s.



<h2 class="wp-block-heading">Economic impact</h2>



Acid rain wasn't just environmental – it was expensive. Acidic precipitation corroded infrastructure, buildings, and monuments. Historic stone structures deteriorated at accelerated rates. Tourism suffered as lakes became fishless and forests declined. EPA economic analyses from the period documented repair costs mounting into billions annually.



<h2 class="wp-block-heading">The solution: government action and technology</h2>



Transformation from crisis to success required unprecedented cooperation between governments, industries, and environmental groups.



<h2 class="wp-block-heading">The Clean Air Act of 1990</h2>



The turning point came with the Clean Air Act Amendments of 1990, signed by President George H.W. Bush. This represented a fundamentally new approach to environmental regulation, as documented in EPA historical records.



<h2 class="wp-block-heading">Cap-and-trade success</h2>



Instead of mandating specific technologies, the 1990 amendments introduced something revolutionary: a cap-and-trade system for sulfur dioxide emissions. EPA program documentation shows this market-based approach set overall limits but allowed companies to trade emission allowances.



The genius was harnessing market forces to find cost-effective pollution reduction. Companies reducing emissions cheaply could sell excess allowances to those facing higher costs. Research published in environmental economics journals and EPA progress reports shows this resulted in dramatic SO2 reduction at a fraction of projected costs.



<h2 class="wp-block-heading">Technology advances</h2>



Policy provided the framework, but technology made reductions possible. Studies in atmospheric science journals document the widespread adoption of flue gas desulfurization systems ("scrubbers") that removed sulfur dioxide before it reached the atmosphere. By the 2000s, new installations could remove over 95% of SO2 emissions, according to EPA technical reports.



The push coincided with cleaner energy development. Natural gas produces fewer sulfur compounds than coal. Wind and solar, emerging in the 1990s, captured growing market share, reducing reliance on high-sulfur coal.



<h2 class="wp-block-heading" id="h-why-we-don-t-hear-about-it-today">Why we don't hear about it today</h2>



Why did acid rain disappear from headlines? Simple: the problem was largely solved.



<h2 class="wp-block-heading">Success doesn't make news</h2>



There's an old journalism saying: "If it bleeds, it leads." Environmental success stories don't generate urgency like crisis reporting. Media attention shifted to other challenges: climate change, plastic pollution, and biodiversity loss. There's only so much environmental anxiety the public can absorb, and newer concerns replaced acid rain.



<h2 class="wp-block-heading">Mission accomplished</h2>



The primary reason is beautifully simple: interventions worked. EPA monitoring data shows sulfur dioxide emissions dropped over 90% since 1990. Academic research published in environmental science journals confirms pH levels in formerly affected areas returned closer to normal. This represents one of history's most dramatic environmental recoveries. Studies by the Adirondack Lakes Survey Corporation show fishless lakes now support healthy populations. Forests recovered, and building damage slowed dramatically.



<h2 class="wp-block-heading" id="h-is-it-really-gone">Is it really gone?</h2>



The crisis is largely resolved, but monitoring data shows the problem isn't completely eliminated – it's managed to acceptable levels. Some areas still experience occasional events during high pollution periods. International environmental research indicates that rapidly industrializing Asian countries face similar problems to what we experienced decades ago, though they're implementing successful strategies.



EPA research shows nitrogen oxide emissions proved more challenging than sulfur dioxide, coming from vehicles and mobile sources. Climate science studies suggest changing weather patterns add complexity to how acid rain forms and falls.



<h2 class="wp-block-heading">What this teaches us</h2>



The acid rain experience proves that seemingly intractable environmental problems can be solved with scientific understanding, political will, and technological innovation. Environmental monitoring data shows recovery speed was remarkable – within a decade, measurable improvements appeared in air quality and ecosystem health.



Success came from bipartisan support across party lines. Policy analysis studies show the market-based approach appealed to those preferring economic incentives while achieving environmental goals. This support created lasting policy surviving political changes.



<h2 class="wp-block-heading">Conclusion</h2>



Acid rain's disappearance from public consciousness represents environmental science's greatest success stories. Through effective regulation, technological innovation, and international cooperation, we transformed an overwhelming crisis into a manageable challenge.



Today's silence isn't because we forgot – it's because we solved it. The 1990 Clean Air Act, combined with technology and energy market changes, reduced acid rain emissions over 90%, according to comprehensive EPA data analysis.



This success offers hope for current challenges. It proves complex problems can be solved when science, policy, and technology work together. As we face climate change and plastic pollution, acid rain reminds us that dramatic positive change is possible.



Next time someone asks whether environmental regulations work, remember acid rain. It's proof that sometimes, we get it right.



<hr class="wp-block-separator has-alpha-channel-opacity"/>



Sources: This article draws from EPA official documentation and progress reports, peer-reviewed research published in environmental and atmospheric science journals, historical data from the Adirondack Lakes Survey Corporation, New York State Department of Environmental Conservation records, US Geological Survey publications, policy analysis studies, and environmental monitoring data collected over three decades.



<h2 class="wp-block-heading">Frequently Asked Questions</h2>



1. Is acid rain completely gone? No, but EPA monitoring shows it's reduced to manageable levels. US sulfur dioxide emissions dropped over 90% since 1990, making acid rain much less severe than the 1980s crisis.



2. How long did solving take? Environmental monitoring data shows significant improvements began within 5-10 years of 1990s emission controls. Full ecosystem recovery took longer – some areas need 20-30 years for complete recovery.



3. What made the solution successful? Clear scientific understanding, visible damage motivating action, bipartisan support, available technology, and innovative market-based policies like cap-and-trade.



4. Do other countries have acid rain problems? Yes, particularly rapidly industrializing Asian countries. However, international environmental research shows many implement similar successful control strategies.



5. Could acid rain return? Potentially, if regulations weaken or we return to high-sulfur coal without controls, though effects would take years to become severe according to environmental projections.



6. Can you recommend any teaching tools on the subject of "acid rain"? The United States Environmental Protection Agency produced a wonderful teacher's guide for ages 14 and under that you can find on the EPA website here: <a href="https://www.epa.gov/sites/default/files/2017-03/documents/teachersguide.pdf" target="_blank" rel="noreferrer noopener">https://www.epa.gov/sites/default/files/2017-03/documents/teachersguide.pdf</a>



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The environmental problem we actually solved

https://www.youtube.com/watch?v=prrq8Ql81zk Acid rain and a crisis solved. Why don't we...

Fresh,Radish,Harvest,On,Soil,In,Garden.

<figure class="wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio"><div class="wp-block-embed__wrapper">
https://youtu.be/Fi2OeEwuzRM?si=vTyd2m9FMmtyWkex
</div></figure>







Mid-July is an opportune time to kick-start a thriving fall garden, and this guide lays out the best vegetables and herbs to plant now for a fruitful autumn harvest. 



Fast-growing leafy greens such as spinach, lettuce, kale, and arugula perform especially well in the waning summer heat, with harvests beginning as soon as 30 days. 



These cool-season crops relish the transition into fall, offering repeated yields with cut-and-come-again methods.



Root vegetables like radishes, carrots, and beets also excel during this period. Radishes deliver satisfaction in under a month, while carrots and beets mature in about two months. Employing succession planting ensures a continuous stream of produce deep into the cooler months. 



For a boost of fresh flavor, herbs like cilantro, basil, dill, and chervil are excellent picks. These heat-loving varieties flourish in July’s warmth and are harvest-ready in about 30 days, especially when sown continuously.



Gardeners in zones 6 through 9 can benefit from planting bush beans and snap peas, which don’t require trellising and are ideal for compact plots. 



Maturing in 50–60 days, they’re a smart choice for quick, protein-rich harvests. For those in hotter regions, heat-tolerant crops such as okra and southern peas provide reliable yields and thrive in scorching conditions.



This guide emphasizes more than crop selection—it highlights the importance of timing, soil preparation, and ongoing sowing techniques. 



With thoughtful planning and attention to regional climate needs, even late-summer gardeners can enjoy fresh salads, hearty stews, and the satisfaction of a robust, homegrown harvest well into fall.



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What to plant in your garden in mid-July

https://youtu.be/Fi2OeEwuzRM?si=vTyd2m9FMmtyWkex Mid-July is an opportune time to kick-start a thriving...

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A new long-term study in Monkton, Vermont, reveals that wildlife tunnels significantly reduce amphibian road mortality during seasonal migrations. 



Frogs and salamanders often cross roads to reach breeding ponds each spring, but many are killed by vehicles. 



Researchers from the <a href="https://www.uvm.edu/" target="_blank" rel="noreferrer noopener">University of Vermont</a>, in collaboration with local citizens and the Vermont Agency of Natural Resources, installed two underpass tunnels in 2015. 



Over a 12-year monitoring period, they observed an 80.2% reduction in amphibian deaths, and up to 94% for non-climbing species like salamanders. 



The study used a before-after-control-impact design and documented more than 5,200 amphibians, highlighting the tunnels’ effectiveness even in nearby buffer zones.



Funded at $342,397 - far cheaper than wildlife crossings for large mammals - the project showcased the power of community-led conservation.



Local groups initiated the effort after observing mass amphibian deaths. Wildlife cameras later captured over 2,200 amphibians using a tunnel in just one spring, along with other species like raccoons and bobcats, indicating wider ecosystem benefits.



This marks the first peer-reviewed, long-term data set in the northeastern U.S. confirming amphibian-specific underpasses work. 



The study urges transportation departments to incorporate these designs into road planning and highlights how community action, thoughtful infrastructure, and persistence can make a real difference for biodiversity.



The full study was published in the <a href="https://linkinghub.elsevier.com/retrieve/pii/S1617138125000780" target="_blank" rel="noreferrer noopener">Journal for Nature Conservation</a>.



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Wildlife tunnels save millions of amphibians

https://youtu.be/XYgiPzmNBTU?si=eFYY7gPHU1JznLvU A new long-term study in Monkton, Vermont, reveals that...

Scientists are transforming chocolate into a functional food by infusing it with probiotics and prebiotics, aiming to create a treat that satisfies cravings while supporting gut health. 



The challenge lies in maintaining chocolate's beloved texture and flavor while adding health benefits.



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Probiotics - beneficial microbes that balance gut bacteria and aid digestion - are typically fragile and can be destroyed by stomach acid or processing. 



Prebiotics act as food for these microbes, helping them thrive. Together, they form "synbiotics," a powerful health combination.



Researchers Smriti Gaur and Shubhi Singh from India's Jaypee Institute of Information Technology took an innovative approach, using natural prebiotics like corn and honey instead of complex processing methods. 



They created five chocolate varieties: a control and four synbiotic versions containing different combinations of prebiotics, probiotics (Lactobacillus strains), and flavor enhancers (cinnamon or orange).



Laboratory simulations of human digestion showed the probiotics remained viable for over five hours, suggesting they could survive long enough to benefit gut health.



Taste tests were positive, with researchers particularly enjoying the orange-flavored variety, describing it as having "vibrant citrus notes" complementing the "rich cocoa" with a "luxurious" texture.



This research represents just the beginning. With further refinement of strains, textures, and flavors, chocolate could evolve beyond mere indulgence to become a functional food that nourishes while it delights.



The study is published in the journal <a href="https://pubs.acs.org/doi/10.1021/acsfoodscitech.4c00741" target="_blank" rel="noreferrer noopener">ACS Food Science &amp; Technology</a>.

Is chocolate the next nutritional powerhouse?

Scientists are transforming chocolate into a functional food by infusing...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Nushagak Bay, a large estuary in southwest Alaska. Nushagak runs mainly north to south and exits in Bristol Bay, a large body of water in the Bering Sea.



"The bay is primarily fed by the Nushagak River, which begins in the Alaska Range and flows southwest approximately 450 km. The bay is also fed by several additional rivers including the Wood, Igushik, Snake and Weary rivers," says ESA.



"The dark colors of the Nushagak River are most likely due to tannins or lignins (chemical substances found in plants). Tannins and lignins from roots, leaves, seeds, bark and soil can leach into the water and give it a brown or even black colour. The sediments then flow southwards where it is mixed with the bluer waters of the bay."



Video/ Image Credit: ESA



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Nushagak Bay in southwest Alaska

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> (ACS) reveals that proteins on flu viruses are actually flexible, tilting and waving in a “breath-like” motion. According to the experts, these proteins could be used to better defend against the flu.



"The main antigenic targets of influenza virus are two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Whereas the structural and dynamical properties of both glycoproteins have been studied previously, the understanding of their plasticity in the whole-virion context is fragmented," wrote the researchers.



To investigate, the team conducted detailed simulations of the influenza A H1N1 virion, or the swine flu. The experts concluded that the visualizations show many new vulnerable states of flu viruses, which could improve future vaccines and antiviral drugs.



Video/ Image Credit: American Chemical Society&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Flu viruses are more flexible than expected

[sendtonews key="G9bUoxcjr4-2511624-12187" type="single"] Today's Video of the Day from the...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Lake Trasimeno, which is located west of Perugia in central Italy. It is the fourth largest lake in the country. While Trasimeno’s water level varies, it has a maximum depth of approximately six meters.&nbsp;



"In this Copernicus Sentinel-2 image, captured on 6 August 2022, the lake’s emerald green colour is likely due to the presence of phytoplankton. Streaks in the water, particularly visible in the west, indicate the presence of soil and sediments which have been stirred up by winds. Dark colored waters in the southern part of the lake indicate a presence of submerged and floating macrophytes (aquatic plants) as well as algae," says ESA.



"Surrounded by hills on three sides, Trasimeno is subject to heavy storms created by winds, especially from the north and west. There are three islets in the lake: Maggiore, Minore and Polvese (the largest). The lake’s shores are sparsely inhabited with only two popular villages: Castiglione del Lago and Passignano sul Trasimeno."



"Italy is experiencing its worst drought in 70 years which has affected drinking water supplies, hydroelectric power and agricultural production. High temperatures, hot winds and lack of rainfall are the main causes of drought in the Umbrian region which saw Lake Trasimeno’s drop 1.3 m, reaching the limit of the hydrometric zero in July 2022."



Video/Image Credit: ESA&nbsp;



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By <a href="http://csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer

Lake Trasimeno in Central Italy

[sendtonews key="3upvlAaHgO-2256633-12187" type="single"] Today’s Video of the Day from the...

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Today's Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> describes a new self-powered nanosensor that can instantly detect mercury contamination with the tap of a finger.&nbsp;



The oxidized form of mercury can be harmful when it is ingested through contaminated water or food. This makes it necessary for experts to develop sensors that can quickly and accurately detect the presence of mercury.&nbsp;



Zong-Hong Lin and colleagues have now created a triboelectric nanosensor (TENS) that can detect mercury by simply by touching a sample. According to the researchers, their TENS could serve as the basis for similar devices to safely and remotely monitor other pollutants.



Video Credit: American Chemical Society&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Detecting mercury contamination with the tap of a finger

[sendtonews key="LvS8v8bp9z-2564889-12187" type="single"] Today's Video of the Day from the...

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Today’s Video of the Day from the <a href="https://www.acs.org/">American Chemical Society</a> explores the ability of salt to transform the way that foods and beverages taste. Salt is known to cover up undesirable flavors, such as bitterness in coffee or beer, but how exactly does sodium chloride change the taste of other compounds?



One previous study showed that, not only does salt suppress bitterness, but also enhances sweetness and sourness. Another study revealed that bitterness reduction by salt seems to be happening at the tongue receptor level as well as in the brain.&nbsp;



While it is known that salt taste is mediated by the presence of sodium channels in the form of taste buds, experts believe that there is also an unknown receptor responsible for how we taste salt that has not yet been identified.&nbsp;



Video Credit: ACS Reactions



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

How does salt makes things taste better?

[sendtonews key="X0f6OHYoI4-2310561-12187" type="single"] Today’s Video of the Day from the...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Santiago, the capital city of Chile. The city is located in the center of the Santiago Metropolitan Region, which has a population of about eight million people.&nbsp;



'The weather of Santiago resembles the Mediterranean climate with dry and warm summers with temperatures reaching up to 35°C (from October to March) and cool and humid winters that can drop to 0°C (from April to September)."



"The city lies in the centre of the country’s central valley around 80 km from the Pacific Ocean to the west and borders Argentina to the east. A tiny part of Argentina is visible in the top-right corner of the image where the mountain crest of the Andes Mountains acts as a divider between the two countries," says ESA.



Video/ Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Santiago, Chile in South America

[sendtonews key="JRaP49ISmm-2357509-12187" type="single"] Today’s Video of the Day from the...

Spiral,Galaxy,,Illustration,Of,Milky,Way

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Astronomers at <a href="https://www.jhu.edu/">Johns Hopkins University</a> have created an interactive map of the universe, including the actual position and real colors of 200,000 galaxies. The map allows the public to access data that was previously only available to scientists.



The map was developed using data collected by the Sloan Digital Sky Survey. For over two decades, a telescope in New Mexico was aimed at slightly different locations to capture the night sky.&nbsp;



"Growing up I was very inspired by astronomy pictures, stars, nebulae and galaxies, and now it's our time to create a new type of picture to inspire people," said map creator Brice Ménard, a professor at Johns Hopkins. "Astrophysicists around the world have been analyzing this data for years, leading to thousands of scientific papers and discoveries. But nobody took the time to create a map that is beautiful, scientifically accurate, and accessible to people who are not scientists. Our goal here is to show everybody what the universe really looks like."



"In this map, we are just a speck at the very bottom, just one pixel. And when I say we, I mean our galaxy, the Milky Way which has billions of stars and planets. We are used to seeing astronomical pictures showing one galaxy here, one galaxy there or perhaps a group of galaxies. But what this map shows is a very, very different scale."



"From this speck at the bottom, we are able to map out galaxies across the entire universe, and that says something about the power of science."



The <a href="https://mapoftheuniverse.net/">interactive map</a> is available online, where it can be downloaded for free.



Video Credit: Johns Hopkins&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Interactive map of the universe includes 200,000 galaxies

[sendtonews key="e4ZG0Jawp3-2374785-12187" type="single"] Astronomers at Johns Hopkins University have created...

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Lesotho: Africa's "Kingdom in the Sky" Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features northwest Lesotho in South Africa.



According to ESA, Lesotho is the only nation in the world that lies completely above 1,000 m in elevation. The country is famous for its tall mountains and narrow valleys, and is known as Africa's "Kingdom in the Sky."



Out of a population of around two million people, about 80 percent live in rural areas. More than 75 percent of these people are engaged in <a href="https://www.earth.com/news/climate-change-will-have-a-global-impact-on-agriculture/">agriculture</a>, including rainfed cereal production and animal grazing.&nbsp;



ESA reports that the country’s agricultural system faces a growing number of issues, with climate-related vulnerabilities such as drought, floods and extreme temperatures occurring more frequently. 



Diamonds are amongst the minerals found in the mountains. Indeed, Lesotho can truly be called the Kingdom in the Sky. Beautiful, culturally rich, safe, affordable, and easily accessible from Durban and Johannesburg, mountainous Lesotho is a vastly underrated travel destination. the Kingdom of Lesotho (Sotho: 'Muso oa Lesotho) is an enclaved country in southern Africa. It is just over 30,000 km2 (11,583 sq mi) in size and has a population of around 2 million.



Video Credit: ESA&nbsp;&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Staff Writer 



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Lesotho: Africa's "Kingdom in the Sky"

[sendtonews key="uV9Lh2fQbV-1760058-12187" type="single"] Lesotho: Africa's "Kingdom in the Sky" Today’s...

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Today's Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features Dublin, the capital and largest city of Ireland. Beyond its pub culture, Dublin is known as a modern culinary destination and a UNESCO City of Literature.



"Dublin is located near the midpoint of Ireland’s east coast in the province of Leinster. The city, which covers an area of around 115 square kilometers, is bordered by the Dublin Mountains, a low mountain range to the south, and is surrounded by flat farmland to the north and west," says ESA.



"The city straddles the River Liffey, which rises in the Wicklow Mountains and flows around 80 kilometers eastwards through the city of Dublin, in which it is canalised and bordered with quays. It then empties into Dublin Bay, an arm of the Irish Sea."



Dublin has an abundance of green spaces, including one of the largest enclosed public parks in any European capital city. Phoenix Park, which was originally formed as a royal hunting park in the 1660s, includes 707 hectares of green space.



Video Credit: ESA&nbsp;



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The city of Dublin on Ireland's east coast

[sendtonews key="qjvhBOBnY8-2426650-12187" type="single"] Today's Video of the Day from the...

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Today's Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the province of Zaragoza in northeast Spain. The image was captured by the Copernicus Sentinel-2 mission.



"Together with the provinces of Huesca and Teruel, Zaragoza formed the old kingdom of Aragon. Its capital, also called Zaragoza (not visible in this image) is home to around half of Aragon’s population," says ESA.



"The Ebro River can be seen winding its way through the province from west to east in this image. Between its source in the Cantabrian Mountains in the northwest and its delta on the Mediterranean coast, the Ebro River is fed by more than 200 tributaries as it flows 910 km across much of northern Spain."



Since rainfall is very scarce in this region, irrigation in the Ebro basin is critically important. In the valleys surrounding the Ebro River, many fields are used for growing crops such as corn, wheat, and barley.



Video/ Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The province of Zaragoza in northeast Spain

[sendtonews key="oL4FnPTGCV-2384527-12187" type="single"] Today's Video of the Day from the...

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Today’s Video of the Day from <a href="https://earthobservatory.nasa.gov/">NASA Earth Observatory</a> reveals the evolution of the Columbia Glacier in southeastern Alaska. Columbia is among the fastest shrinking glaciers in the world, and the video documents its rapid retreat over the years.&nbsp;



Columbia Glacier is a large, multi-branched calving glacier that flows out of the Chugach Mountains to the Prince William Sound.&nbsp;



According to USGS, Columbia had a long history of stability prior to 1980, with a length 41 miles, and small, short-lived advances or retreats.



In the years since 1980, however, satellite images have captured Columbia’s alarming retreat. By using false-color images, scientists can distinguish between snow and ice, open water, vegetation, and rocky debris on the glacier’s surface.



The series of false-color images featured in today's video were acquired over the span of 35 years. You can see that by 2021, the glacier’s main branch had retreated about 15 miles from its initial position.



The Columbia Glacier has also lost more than 50 percent of its volume, mostly due to calving. <a href="https://www.earth.com/video/nasa-reveals-3d-visual-of-an-atmospheric-river/">NASA</a> reports that while climate change likely started the retreat, mechanical processes kept the disintegration going.



The NASA images are provided by Jesse Allen, Robert Simmon, Joshua Stevens, and Lauren Dauphin using data from Landsat satellites, from the U.S. Geological Survey, and data from MODIS on NASA’s Terra satellite. The structure of Columbia’s moraine played a large role in the stability of the glacier before 1980. 



Like other tidewater glaciers, the Columbia built up a moraine over time, and the mixture of ice and rock functioned like a dam keeping out the sea. It was supported on one end by the shoreline and by the underwater terminal moraine at the other.



Video Credit: NASA Earth Observatory/&nbsp; NASA’s Scientific Visualization Studio



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The rapid retreat of the Columbia Glacier

[sendtonews key="0879czfG3k-1785905-12187" type="single"] Today’s Video of the Day from NASA...

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Today’s Video of the Day from the <a href="https://www.esa.int/">European Space Agency</a> features the Pyrenees Mountains, which form a natural boundary between France and Spain in southwest Europe.



The mountain range is 430 kilometers in length. It stretches from the Mediterranean Sea on the east to the Atlantic Ocean on the west.



At an elevation of 3404 meters, Pico de Aneto is the highest mountain peak in the Pyrenees, and the third-highest peak in Spain. Pico de Aneto is located in the Posets-Maladeta Natural Park, which spans more than 82,000 acres.&nbsp;



"Geological studies have revealed that the Pyrenees Mountains have been around for longer than the Alps, with their sediments first deposited in coastal basins during the Paleozoic and Mesozoic eras," reports ESA.



"The entire mountain range formed due to the upwelling of large sedimentary rocks by the collision of the Iberian and the Eurasian plate around 100 to 150 million years ago, followed by intense erosion from ice and water."



The western Pyrenees receive more precipitation due to moisture blowing in from the Atlantic Ocean. The mountain range contains many lakes, several small glaciers, and some of the highest waterfalls in Europe.



Video &amp; Image Credit: ESA



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

The Pyrenees Mountains in southwest Europe

[sendtonews key="6HyfrAJTBI-1831843-12187" type="single"] Today’s Video of the Day from the...

Earth,Like,Exoplanet,3d,Render

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Today's Video of the Day from <a href="https://www.nasa.gov/goddard">NASA Goddard</a> describes two exoplanets that are orbiting a star 218 light-years away. A team of researchers led by the University of Montreal has found evidence that these planets are "water worlds."



The experts used data from NASA’s Hubble and Spitzer Space Telescopes. They discovered that exoplanets Kepler-138 c and Kepler-138 could be composed largely of water.



"We previously thought that planets that were a bit larger than Earth were big balls of metal and rock, like scaled-up versions of Earth, and that's why we called them super-Earths," explained study co-author Björn Benneke.&nbsp;



"However, we have now shown that these two planets, Kepler-138 c and d, are quite different in nature and that a big fraction of their entire volume is likely composed of water. It is the best evidence yet for water worlds, a type of planet that was theorized by astronomers to exist for a long time."



Video Credit: NASA Goddard



Image Credit: NASA, ESA, and Leah Hustak (STScI)



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By <a href="mailto:csexton@earth.com">Chrissy Sexton</a>, <a href="https://www.earth.com/staff/">Earth.com</a> Editor



Check us out on <a href="https://www.earth.com/earthsnap/">EarthSnap</a>, a free app brought to you by Eric Ralls and Earth.com.

Two distant planets may be "water worlds"

[sendtonews key="QIoVYJqRBi-2434608-12187" type="single"] Today's Video of the Day from NASA...

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