# data[].attributes.body
Animals adapt to their environment so they can survive. Whether it is a behavioral adaptation where animals huddle up for warmth or a biological adaptation where animals have better ears so they can hear prey.

# data[].attributes.attachment_link.readable_text
Biology, Ecology, Conservation

Image

Photograph by Paul Zahl

In evolutionary theory, adaptation is the biological mechanism by which organisms adjust to new environments or to changes in their current environment. Although scientists discussed adaptation prior to the 1800s, it was not until then that Charles Darwin and Alfred Russel Wallace developed the theory of natural selection.

Wallace believed that the evolution of organisms was connected in some way with adaptation of organisms to changing environmental conditions. In developing the theory of evolution by natural selection, Wallace and Darwin both went beyond simple adaptation by explaining how organisms adapt and evolve. The idea of natural selection is that traits that can be passed down allow organisms to adapt to the environment better than other organisms of the same species. This enables better survival and reproduction compared with other members of the species, leading to evolution.

Organisms can adapt to an environment in different ways. They can adapt biologically, meaning they alter body functions. An example of biological adaptation can be seen in the bodies of people living at high altitudes, such as Tibet. Tibetans thrive at altitudes where oxygen levels are up to 40 percent lower than at sea level. Breathing air that thin would cause most people to get sick, but Tibetans' bodies have evolved changes in their body chemistry. Most people can survive at high altitudes for a short time because their bodies raise their levels of hemoglobin, a protein that transports oxygen in the blood. However, continuously high levels of hemoglobin are dangerous, so increased hemoglobin levels are not a good solution to high-altitude survival in the long term. Tibetans seemed to have evolved genetic mutations that allow them to use oxygen far more efficently without the need for extra hemoglobin.

Organisms can also exhibit behavioral adaptation. One example of behavioral adaptation is how emperor penguins in Antarctica crowd together to share their warmth in the middle of winter.

Scientists who studied adaptation prior to the development of evolutionary theory included Georges Louis Leclerc Comte de Buffon. He was a French mathematician who believed that organisms changed over time by adapting to the environments of their geographical locations. Another French thinker, Jean Baptiste Lamarck, proposed that animals could adapt, pass on their adaptations to their offspring, and therefore evolve. The example he gave stated the ancestors of giraffes might have adapted to a shortage of food from short trees by stretching their necks to reach higher branches. In Lamarck's thinking, the offspring of a giraffe that stretched its neck would then inherit a slightly longer neck. Lamarck theorized that behaviors aquired in a giraffe's lifetime would affect its offspring. However, it was Darwin's concept of natural selection, wherein favorable traits like a long neck in giraffes suvived not because of aquired skills, but because only giraffes that had long enough necks to feed themselves survived long enough to reproduce. Natural selection, then, provides a more compelling mechanism for adaptation and evolution than Lamarck's theories.

National Geographic Society

July 14, 2022

# data[].attributes.attachment_link.description
Evolutionary adaptation, or simply adaptation, is the adjustment of organisms to their environment in order to improve their chances at survival in that environment.

# data[].attributes.body
A omnivore is an organism that eats meat and plants. Many Mammals are omnivores such as Humans, Black Bears, Pigs, and Dogs. Omnivores have sharp teeth and flat molars to help rip meat and crush plant material.

# data[].attributes.attachment_link.description
An omnivore is an organism that regularly consumes a variety of material, including plants, animals, algae, and fungi. They range in size from tiny insects like ants to large creatures—like people.

# data[].attributes.body
A carnivore is an organism that mostly eats meat or the flesh of animals. Many carnivores eat herbivores (an animal that eats plants). Obligate carnivores are carnivores that only eat meat because plants don't give them enough nutrition. Some animals that are carnivores are Cougars, Humpback whales, Mantis, etc. Carnivores have biological adaptions that help them hunt Animals easier, wolves have strong jaws and long teeth to rip apart an organism.

# data[].attributes.attachment_link.description
A carnivore is an organism that eats mostly meat, or the flesh of animals. Sometimes carnivores are called predators.

# data[].attributes.body
A herbivore is an organism that mostly feeds. on plants. Herbivores range from tiny insects to elephants. Some animals that are herbivores are Gorillas, Cattle (Cows), Green Sea Turtle, and HoneyBees. Herbivores have biological adaptations that help them eat and grind up plant material easier (Herbivores have wide molars).

# data[].attributes.attachment_link.readable_text
An herbivore is an organism that feeds mostly on plants. Herbivores range in size from tiny insects such as aphids to large, lumbering elephants.

An herbivore is an organism that mostly feeds on plants. Herbivores range in size from tiny insects such as aphids to large, lumbering elephants.

Herbivores are a major part of the food web, a description of which organisms eat other organisms in the wild. Organisms in the food web are grouped into trophic, or nutritional, levels. There are three trophic levels. Autotrophs, organisms that produce their own food, are the first trophic level. These include plants and algae. Herbivores, which eat autotrophs, are the second trophic level. Carnivores, organisms that consume animals, and omnivores, organisms that consume both plants and animals, are the third trophic level.

Autotrophs are called producers, because they produce their own food. Herbivores, carnivores, and omnivores are consumers. Herbivores are primary consumers. Carnivores and omnivores are secondary consumers.

Herbivores often have physical features that help them eat tough, fiberous plant matter. Unlike herbivores and other consumers, autotrophs have tough cell walls throughout their physical structure. Cell walls can make plant material difficult to digest.

Many herbivorous mammals have wide molars. These big teeth help them grind up leaves and grasses. Carnivorous mammals, on the other hand, usually have long, sharp teeth that help them grab prey and rip it apart.

A group of herbivores called ruminants have specialized stomachs. For the digestion of plant matter, ruminant stomachs have more than one chamber. When a ruminant chews up and swallows grass, leaves, and other material, it goes into the first chamber of its stomach, where it sits and softens. There, specialized bacteria break down the food. When the material is soft enough, the animal regurgitates the food and chews it again. This helps break down the plant matter. This partially digested food is called cud. The animal then swallows the cud, and it goes into a second chamber of the stomach. Chemicals in the second chamber digest the plant material further, and it goes into the third chamber. Finally, the digested food goes to the fourth chamber, which is similar to a human stomach. Sheep, deer, giraffes, camels, and cattle are all ruminants.

Picky Eaters

Some herbivores eat any plant matter they can find. Elephants, for example, eat bark, leaves, small branches, roots, grasses, and fruit. Black rhinoceroses also eat a variety of fruits, branches, and leaves.

Other herbivores eat only one part of a plant. An animal that specializes in eating fruit is called a frugivore. Oilbirds, which live in northern South America, are frugivores. They eat nothing but the fruit of palms and laurels. The koala, which is native to Australia, eats little besides the leaves of eucalyptus trees. An animal that eats the leaves and shoots of trees is called a folivore. Pandas, which feed almost exclusively on bamboo, are folivores. Termites are insects that feed mostly on wood. Wood-eaters are called xylophages.

Many insects are herbivores. Some, such as grasshoppers, will eat every part of a plant. Others specialize in certain parts of the plant. Aphids drink sap, a sticky fluid that carries nutrients through the plant. Caterpillars eat leaves. The larvae, or young wormlike forms, of root weevils feed on roots. Asian long-horned beetles tunnel deep into the heart of a tree and eat the wood there. Honeybees feed on nectar and pollen from flowers.

Some herbivores consume only dead plant material. These organisms are called detritivores. Detritivores also consume other dead organic material, such as decaying animals, fungi, and algae. Detritivores such as earthworms, bacteria, and fungi are an important part of the food chain. They break down the dead organic material and recycle nutrients back into the ecosystem. Detritivores can survive in many places. Earthworms and mushrooms live in the soil. There are also detritivore bacteria at the bottom of the ocean.

Plants that are parasites can still be considered herbivores. A parasite is an organism that lives on or in another organism and gets its nutrients from it. Parasitic plants get their nutrients from other plants, called host plants. Dodder, native to tropical and temperate climates around the world, is a parasitic vine that wraps around a host plant. Dodder has rootlike parts called haustoria that attach to the host plant, so it can feed on its nutrients. Eventually, the parasitic dodder feeds on all the nutrients of the host plant, and the host plant dies. The dodder vines then move on to another plant.

Herbivores in the Food Chain

Many herbivores spend a large part of their life eating. Elephants need to eat about 130 kilograms (300 pounds) of food a day. It takes a long time to eat that much leaves and grass, so elephants sometimes eat for 18 hours a day.

Herbivores depend on plants for their survival. If the plant population declines, herbivores cannot get enough food. Beavers, for example, feed on trees and plants that live near water. If the trees are removed to build houses and roads, the beaver population cannot survive.

Similarly, many carnivores need herbivores to survive. Herbivorous zebras and gazelles once traveled in great herds across the savannas of Africa. But these herds have shrunk and are now mostly confined to parks and wildlife reserves. As the number of these herbivores declines, carnivores such as African wild dogs, which prey on them, also decline. Scientists estimate that only 3,000 to 5,500 African wild dogs remain in the wild.

In some places, the disappearance of large carnivores has led to an overpopulation of herbivores. Wolves and cougars are traditional predators, or hunters, of white-tailed deer, which are herbivores. Hunting and expanding human settlements have practically eliminated these predators from the northeastern United States. Without its natural predators, the population of white-tailed deer has skyrocketed. In some areas, there are so many deer that they cannot find enough food. They now frequently stray into towns and suburbs in search of food.

Fast Fact

Watch Those Teeth
Many herbivores have large, dull, flat teeth. These teeth are excellent for chewing and breaking down tough plant material. Carnivores have sharp, narrow teeth that are better for biting and tearing flesh.

However, some herbivores also have strong, sharp teeth. These teeth, such as those on hippopotamuses and gorillas, are not adapted for eating. They have developed for confrontations with other animals-fighting, not feeding.

Media Credits

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Illustrators

Mary Crooks, National Geographic Society

Editors

Jeannie Evers, Emdash Editing, Emdash Editing

Producer

National Geographic Society

other

Last Updated

July 15, 2022

For information on user permissions, please read our Terms of Service. If you have questions about licensing content on this page, please contact ngimagecollection@natgeo.com for more information and to obtain a license. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. She or he will best know the preferred format. When you reach out to him or her, you will need the page title, URL, and the date you accessed the resource.

Media

If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

Text

Text on this page is printable and can be used according to our Terms of Service.

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

# data[].attributes.attachment_link.description
An herbivore is an organism that feeds mostly on plants. Herbivores range in size from tiny insects such as aphids to large, lumbering elephants. An herbivore is an organism that mostly feeds on plants. Herbivores range in size from tiny insects such as aphids to large, lumbering elephants.

# data[].attributes.headline
How Ducks and Geese have adapted to water

# data[].attributes.subject
How Ducks and Geese have adapted to water

# data[].attributes.body
Both Ducks and Geese have webbed feet. Webbed feet allow Duck and Geese to paddle through water easily (help them escape from predators) Both Duck and Geese are omnivores meaning they eat both meat and plants. Both Duck's and Geese's are Waterbirds (can't fly)

# data[].attributes.attachment_link.readable_text
Ducks, geese, and swans all have webbed feet. The primary use for webbed feet is paddling through water.

Here's how it works: as the bird pulls its foot backwards through the water, the toes spread apart, causing the webs to spread out. The webs push more water than just a bird foot with spread-out toes would push. (It would be like trying to swim with your fingers spread apart.) The webbed feet propel the bird through the water.

When the bird pulls its foot forward for the next push, the toes come together, folding up the webs. The foot is instantly less resistant, moving through the water easily to get into place for the next stroke without pushing the bird backwards.

Webbed feet are useful on land as well as on water because they allow birds to walk more easily on mud.

There are actually two different kinds of webbed feet:

Some birds like the Northern Pintail or Mallard have webbing between three of their toes. Each bird has a fourth toe located behind the webbing that does not help in propelling the bird through the water. This type of webbed foot is known as palmate - that is, shaped like an open hand or palm.

The other type of webbed foot has webbing between all four of the bird's toes. This type of webbed foot is known as totipalmate - "toti" meaning total and "palmate" meaning open hand or palm.

Most swimming or paddling birds have their legs and feet located at the rear of their body. This adaptation is an advantage on the water - it helps to propel the birds along.

But what's good on the water isn't necessarily good on land. Having their legs and feet located at the rear of their body makes walking more difficult for these birds.

# data[].attributes.attachment_link.authors[].name
Interactive Media - Nebraska Educational Telecommunications

# data[].attributes.attachment_link.title
Project Beak: Adaptations: Feet: Swimming

# data[].attributes.attachment_link.description
Ducks, geese, and swans all have webbed feet. The primary use for webbed feet is paddling through water. Here's how it works: as the bird pulls its foot backwards through the water, the toes spread apart, causing the webs to spread out. The webs push more water than just a bird foot with spread-out toes would push.

# data[].attributes.body
The Tyrannosaurus Rex (T-Rex) was a huge Dinosaur that weighed between 5.5-8 tons, and could be up to 40 feet long and 12 feet high. The T-Rex had jaws strong enough to destroy cars, and had super sharp teeth to eat meat. Everyone knows that the T-Rex had small arms, but why? The T-Rex had small arms to slash prey in close contact. The reason the T-Rex and Dinosaurs went extinct was due to the large asteroid that hit earth 66 Million years ago.

# data[].attributes.attachment_link.readable_text
Common Name:

Tyrannosaurus rex

Scientific Name:

Tyrannosaurus rex

Type:

Prehistoric Animals

Size:

40 feet long and 12 feet tall

Weight:

Between 5.5 and eight tons

Size relative to a bus:

Tyrannosaurus rex was one of the most ferocious predators to ever walk the Earth. With a massive body, sharp teeth, and jaws so powerful they could crush a car, this famous carnivore dominated the forested river valleys in western North America during the late Cretaceous period, 68 million years ago.

Although T. rex is a household name, what we know about this tyrannosaur is constantly evolving. Improved technologies, such as biomechanical modeling and x-ray imaging, have allowed scientists to gain a deeper understanding of how this apex predator lived.

Strengths

Tyrannosaurus rex, whose name means " king of the tyrant lizards," was built to rule. This dinosaur's muscular body stretched as long as 40 feet-about the size of a school bus-from its snout to the tip of its powerful tail. Weighing up to eight tons, T. rex stomped headfirst across its territory on two strong legs. These dinosaurs likely preyed on living animals and scavenged carcasses-and sometimes they even ate one another.

The head of a T. rex was the real stuff of nightmares. This fierce carnivore was optimally built for crunching through its meals, with a stiff skull that allowed it to channel all the force of its muscles into one bite- delivering up to six tons of pressure. This dinosaur used its 60 serrated teeth, each about eight inches long, to pierce and grip flesh, throwing prey into the air and swallowing it whole. To keep itself from overheating while crushing prey with its mighty jaws, the giant animal had vents in its head to help its brain stay cool, similar to those found in alligators.

Tyrannosaurus rex was also adept at finding its prey thanks to a keen sense of smell. While scientists have known for a while that this dinosaur devoted large portions of its brain to processing smell, studies have recently revealed that T. rex had almost as many genes encoding its olfactory receptors as a house cat does today. This powerful snout also likely helped T. rex find mates and detect other predators.

Weaknesses

Not everything about Tyrannosaurus rex was fierce, however. This dinosaur had unexpectedly puny arms, and the function of these little limbs is a source of debate among scientists. Some believe the animal's arms were an evolutionary leftover-like the pelvic bones of a snake-or served non-predatory purposes like helping it grip a mate. Others argue that T. rex's arms may have been adapted for " vicious slashing " at close quarters, given their ability to inflict deep wounds with four-inch claws.

And while they had strong thighs, these dinosaurs were not speedy. They could only walk briskly at up to 12 miles an hour-likely not fast enough to chase a speeding Jeep, as depicted in the movie Jurassic Park. Using biomechanical models, scientists have theorized that if these heavy animals moved any faster, they would have shattered the bones in their feet.

Growth spurts and extinction

Tyrannosaurus rex had a life expectancy of about 28 years. Previous studies have suggested that it went through a growth spurt in its teenage years, but until recently, scientists didn't know much about how it grew from a hatchling to a powerful predator.

In January 2020, a study of the fossils of Nanotyrannus-a smaller tyrannosaur that was believed to have lived alongside T. rex-revealed that the bones were more likely from a juvenile T. rexthan another species. If so, the study then suggests that Tyrannosaurus rex's growth rate varied as it aged, and it could slow down its growth when food was scarce, a major evolutionary advantage.

In spite of all its advantages, T. rex was no match for the mass extinction event that claimed three quarters of life on Earth 66 million years ago. This cataclysm occurred when an asteroid or comet the size of a mountain slammed into Earth, wiping out Tyrannosaurus rex along with the rest of the non-avian dinosaurs and bringing a sudden end to the Cretaceous period.

# data[].attributes.attachment_link.description
Named the "king of the tyrant lizards," T. rex was built to rule. Find out how these dinosaurs lived, what made them so vicious, and what we're still learning about them today.

# data[].attributes.body
The Wooly Mammoth was a Mammoth that lived during the last Ice age. The Wooly Mammoth weighed up to six tons. They went extinct due to warmer climates and humans hunting them. Unfortunately they weren't able to adapt to the warmer climate.

# data[].attributes.attachment_link.description
Woolly mammoths are extinct relatives of today's elephants. They lived during the last ice age, and they may have died off when the weather became warmer and their food supply changed. Humans may also be partly responsible for their disappearance due to hunting.

# data[].attributes.body
The Dodo bird was a flightless bird that lived on islands in the Indian oceans. The Dodo weighed about 50 pounds and was a little bigger than a turkey. The Dodo went extinct in 1681 due to humans hunting them and introducing more animals to the islands.

# data[].attributes.attachment_link.readable_text
Table of Contents

This article was most recently revised and updated by

dodo, ( Raphus cucullatus), extinct flightless bird of Mauritius (an island of the Indian Ocean), one of the three species that constituted the family Raphidae, usually placed with pigeons in the order Columbiformes but sometimes separated as an order (Raphiformes). The other two species, also found on islands of the Indian Ocean, were the solitaires ( Raphus solitarius of Réunion and Pezophaps solitaria of Rodrigues). The birds were first seen by Portuguese sailors about 1507 and were exterminated by humans and their introduced animals. The dodo was extinct by 1681, the Réunion solitaire by 1746, and the Rodrigues solitaire by about 1790. The dodo is frequently cited as one of the most well-known examples of human-induced extinction and also serves as a symbol of obsolescence with respect to human technological progress.

The dodo, bigger than a turkey, weighed about 23 kg (about 50 pounds). It had blue-gray plumage, a big head, a 23-cm (9-inch) blackish bill with reddish sheath forming the hooked tip, small useless wings, stout yellow legs, and a tuft of curly feathers high on its rear end. The Réunion solitaire may have been a white version of the dodo. The brownish Rodrigues solitaire was taller and more slender, with smaller head, short bill lacking the heavy hook, and wings with knobs. All that remains of the dodo is a head and foot at Oxford, a foot in the British Museum, a head in Copenhagen, and skeletons, more or less complete, in various museums of Europe, the United States, and Mauritius. Many bones of solitaires have also been preserved.

The dodo's prominent role in bringing attention to the extinction of species, coupled with advances in genetics that could allow for its resurrection ( de-extinction), have led scientists to consider the possibility of bringing the dodo back. The sequencing of the dodo genome by geneticists in 2016 reinvigorated this discussion as well as the ethical debate of using de-extinction techniques to alter natural history.

The Editors of Encyclopaedia Britannica John P. Rafferty.

# data[].attributes.attachment_link.description
dodo, (Raphus cucullatus), extinct flightless bird of Mauritius (an island of the Indian Ocean), one of the three species that constituted the family Raphidae, usually placed with pigeons in the order Columbiformes but sometimes separated as an order (Raphiformes).

# data[].attributes.headline
A carnivore that was endangered but isn't anymore

# data[].attributes.subject
A carnivore that was endangered but isn't anymore

# data[].attributes.body
The Gray Wolf was endangered in the 1970s due to lack of prey and conflicts with farmers and ranchers. Since then the Gray Wolf population has steadily increased, and today it's estimated that there are 6,000 Gray Wolves in the U.S

# data[].attributes.attachment_link.title
Gray wolves taken off U.S. endangered species list in controversial move

# data[].attributes.attachment_link.description
Though the predators occupy a small portion of their former range, the government claims they've recovered. Wildlife groups disagree.