Multiple species exhibit convergent evolution by developing crab-like features

The marine animals that rely on coral reefs for habitats, camouflage, and food

Parrotfish and surgeonfish feed on algae that grow on coral reefs to prevent overgrowth while serving as prey for larger fish across the food chain. Reefs also serve as structures for organisms like sea anemones, which provide shelter for clownfish, and homes for invertebrates such as crabs, lobsters, and shrimp, which help recycle nutrients.

Explore the independent lines of evidence behind the theory of evolution

Gradual changes in organisms have been directly observed through artificial selection—humans purposely selecting organisms to breed to pass on specific traits—and in organisms with short lifespans, such as insects and microbes. Analyses of DNA and anatomical structures across different species, as well as fossil records, also reveal ancient shared ancestry consistent with natural selection.

The first appearance of bioluminescence was at least 540 million years ago

After analyzing fossils, genetic data, and statistical methods, scientists believe octocorals were the first organisms to evolve light-producing abilities. As a result of independent evolution across at least 94 species, this phenomenon is connected to a diverse range of behaviors.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

Explore case studies of each type of convergent plate boundary

At these boundaries, a collision of two oceanic plates produces a curved chain of volcanic islands, like those seen in the Caribbean. A continental-continental plate collision results in plates buckling upward, forming large mountain ranges.

Meet Cystisoma, the 7-inch crustacean with eyes for a head

In deep midwater, roughly 1,000 feet below the water's surface, completely transparent Cystisoma hide in plain sight from predators. Their retinas are splayed out thin across their disproportionately large eyes to avoid detection, and their entire bodies are transparent, difficult to see even as they are held in the palm of your hand. Learn more about the creatures here.

Coevolution of pollinators and flowering plants diversified both

The first pollinators were beetles, which consumed pollen before flowering plants existed. Over time, plants evolved to attract more insects and improve the uptake of pollen, while insects adapted their biology to enhance the capture of pollen, such as developing specialized mouthparts.

The Southern Ocean's powerful circular current isolates organisms in its environment

The spiralling current churns up nutrients across the frigid waters, leading to the evolution of fantastical organisms, including century-old starfish and colossal squid, and unique adaptations, including the icefish's clear blood and organic antifreeze, over the past 30 million years.

The gene that changes sharks to skates

Sharks and skates (similar to stingrays, without the stinger) look different enough that it's reasonable to assume they aren't related. However, a new study suggests that a microscopic change at the cellular level caused skates to branch off from sharks as they evolved. Scientists believe roughly 285 million years ago, the 3D structure of shark DNA shifted, disrupting the relationships between key genes, and resulting in the flat, symmetrical shape of modern skates.

The economics of horseshoe crab blood

Horseshoe crabs are older than dinosaurs and have survived five mass extinctions that wiped most life from the planet. But it's only now that their future as a species is in danger. This blood, worth about $60,000 per gallon, is hyper-sensitized to certain bacteria that are fatal to humans. This 17-minute podcast dives into humanity's pursuit of horseshoe crab blood, a "somewhat magical" mixture heavily relied on by the pharmaceutical industry.

Humans won't develop more than 5 fingers because it would impact too many body parts

All modern animals have five or fewer digits on each of their limbs. Roughly 348 million years ago, at least two species had eight: the Ichthyostega and the Acanthostega. According to Dollo's law, complex evolved features are very unlikely to recur in evolution. Researchers believe humans won't develop more than five digits because it would impact other body parts too much.

What a tiny marine worm can tell us about our brains

Meet the amphioxus, a small eel-like animal that has a lot to teach us about brain evolution. The genetic roots of our brains can be seen in these unusual creatures. This three-minute educational video focuses on the evolutionary history of the human brain through these odd little critters with a 500-million-year-old history.

Some invasive species can provide benefits to ecosystems over time

In the 1990s, round gobies were introduced into the Great Lakes, rapidly spreading and competing with local sculpin and logperch. However, Lake Erie watersnakes, which were on the endangered species list, shifted their diet to be almost entirely made up of the plentiful round gobies, contributing to their loss of endangered status in 2011.

About 1,500 species of tardigrades have been identified by their unique physiology

Freshwater-bound eutardigrades live on mosses and lichens and are distinguished by variations in the shape and number of claws at the end of their legs. Marine heterotardigrades, which live on algae and deep-sea sediments, have been observed to possess feathers, inflatable appendages, and flagpole-like tails.

Dinosaurs are defined by specific traits that many dinosaur-like creatures lack

Although pterodactyls, mosasaurs, crocodilians, and other organisms are mistaken for dinosaurs, they do not have upright legs or specific hip structures characteristic of the terrestrial reptiles. Some, like the Dimetrodon, are more closely related to humans than dinosaurs.

Tigers emerged much earlier as a species than lions

Both lions and tigers are iconic big cats known for their size and power, but they remain distinct species. Beyond just looking different, they can exhibit very different behaviors. For example, tigers are significantly less social than lions, who live in social matriarchal groups. Tigers and lions are unlikely to ever interact in the wild, but humans have artificially bred them in captivity, creating a "liger."

Neanderthals commonly had surfer's ear, a potential sign of extensive seafood collection

Analysis from 2019 found that about half of the 23 Neanderthal skulls scientists examined seemed to have the bony growths in the inner ear, signifying they had surfer's ear. Those growths suggest our ancient relatives, dating back to between perhaps 100,000 and 40,000 years ago, were potentially hunting fish, mollusks, or other marine resources in chilly waters.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Foghorn honks helped duckbills set the mood

Examining the unique crest of the Parasaurolophus, which researchers think allowed the creatures to emit loud, unique vocalizations as part of their social interactions.

Organisms can possess multiple unique sets of DNA in one body

Genetic chimeras can result when cells with different DNA combine, such as when two sperm cells fertilize two egg cells, creating two embryos that then merge. In mosaicism, mutations arise within an organism after conception and can spread through cell division, resulting in diseases and forming genetically distinct anatomy.

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

Depending on environment, aliens' bodies would have wide-ranging possibilities

Humans tend to imagine aliens as humanlike, but that's probably unlikely. From small space spiders to metallic carnivores, life on other planets—and how we could interact with it—is difficult to imagine.

Seven known types of coronaviruses have jumped from animals to humans

Coronaviruses, including SARS-CoV-2, belong to a large family of viruses characterized by their crown-like appearance under a microscope, due to spike proteins on their surface. While thousands are believed to exist in animals, only seven are known to have made the jump to humans.

A fascinating look at why cucumber tendrils coil in opposite directions

The tendrils of cucumber plants coil when they hit a surface, creating a distinct telephone-cord look. Charles Darwin wrote about the mystery in the 1850s, though it wasn't until the 21st century that scientists figured out just how mysterious the coil is: its tendrils coil in opposite directions.

Distinguishing the three types of mineral deposits collected via deep-sea mining

The greatest interest is in polymetallic nodules—structures formed from metals in seawater collecting around a core of shell, bone, or rock. Cobalt-rich ferromanganese crusts cover underwater mountain ranges and form over millions of years of metal deposition. Polymetallic sulfide deposits accumulate when seawater seeps into volcanic rocks.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

See a dying star in different wavelengths

The Crab Nebula is the remnants of a dying star that went supernova . First spotted a thousand years ago by Chinese and Japanese astronomers, and likely Native Americans as well. Its original bright light has long since faded, but you can see it in different light wavelengths through this interactive website.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

The animatronic shark from Steven Spielberg's 'Jaws,' the first modern blockbuster, was a complex underwater apparatus called 'Bruce.'

The American cockroach is actually from Africa, an apparent hitchhiker aboard ships carrying enslaved people, with evidence suggesting the bug may have arrived in the New World as early as the 1600s.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

Before humans, the Soviet Union and the United States sent animals—including apes, dogs, and cats—to space during the Space Race.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

20,000 letters to the advice columnist 'Dear Abby' provide insight into prevailing sex, religion, and LGBTQ fears, anxieties, and concerns from the 1950s onward.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.