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Encyclopedic Entry adaptation

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An adaptation is a mutation, or genetic change, that helps an organism, such as a plant or animal, survive in its environment. Due to the helpful nature of the mutation, it is passed down from one generation to the next. As more and more organisms inherit the mutation, the mutation becomes a typical part of the species. The mutation has become an adaptation.

Structural and Behavioral Adaptations

An adaptation can be structural, meaning it is a physical part of the organism. An adaptation can also be behavioral, affecting the way an organism acts.

An example of a structural adaptation is the way some plants have adapted to life in the desert. Deserts are dry, hot places. Plants called succulents have adapted to this climate by storing water in their thick stems and leaves.

Animal migration is an example of a behavioral adaptation. Grey whales migrate thousands of miles every year as they swim from the cold Arctic Ocean to the warm waters off the coast of Mexico. Grey whale calves are born in the warm water, and then travel in groups called pods to the nutrient-rich waters of the Arctic.

Some adaptations are called exaptations. An exaptation is an adaptation developed for one purpose, but used for another. Feathers were probably adaptations for keeping the animal warm that were later used for flight, making feathers an exaptation for flying.

Some adaptations, on the other hand, become useless. These adaptations are vestigial: remaining but functionless. Whales and dolphins have vestigial leg bones, the remains of an adaptation (legs) that their ancestors used to walk.

Habitat Adaptations usually develop in response to a change in the organisms habitat.

A famous example of an animal adapting to a change in its environment is the English peppered moth. Prior to the 19th century, the most common type of this moth was cream-colored with darker spots. Few peppered moths displayed a mutation of being grey or black. As the Industrial Revolution changed the environment, the appearance of the peppered moth changed. The darker-colored moths, which were rare, began to thrive in the urban atmosphere. Their sooty color blended in with the trees stained by industrial pollution. Birds couldnt see the dark moths, so they ate the cream-colored moths instead. The cream-colored moths began to make a comeback after the United Kingdom passed laws that limited air pollution. 1 of 5 Speciation

Sometimes, an organism develops an adaptation or set of adaptations that create an entirely new species. This process is known as speciation.

The physical isolation or specialization of a species can lead to speciation.

The wide variety of marsupials in Oceania is an example of how organisms adapt to an isolated habitat. Marsupials, mammals that carry their young in pouches, arrived in Oceania before the land split with Asia. Placental mammals, animals that carry their young in the mothers womb, came to dominate every other continent, but not Oceania. There, marsupials faced no competition.

Koalas, for instance, adapted to feed on eucalyptus trees, which are native to Australia. The extinct Tasmanian tiger was a carnivorous marsupial and adapted to the niche filled by big cats like tigers on other continents. Marsupials in Oceania are an example of adaptive radiation, a type of speciation in which species develop to fill a variety of empty ecological niches.

The cichlid fish found in Africas Lake Malawi exhibit another type of speciation, sympatric speciation. Sympatric speciation is the opposite of physical isolation. It happens when species share the same habitat. Adaptations have allowed hundreds of varieties of cichlids to live in Lake Malawi. Each species of cichlid has a unique, specialized diet: One type of cichlid may eat only insects, another may eat only algae, another may feed only on other fish.

Coadaptation

Organisms sometimes adapt to and with other organisms. This is called coadaptation. Certain flowers have adapted their pollen to appeal to the hummingbirds nutritional needs. Hummingbirds have adapted long, thin beaks to extract the pollen from certain flowers. In this relationship, the hummingbird gets food, while the plants pollen is distributed. The coadaptation is beneficial to both organisms.

Mimicry is another type of coadaptation. With mimicry, one organism has adapted to resemble another. The harmless king snake (sometimes called a milk snake) has adapted a color pattern that resembles the deadly coral snake. This mimicry keeps predators away from the king snake.

The mimic octopus has behavioral as well as structural adaptations. This species of octopus can mimic the look and movements of animals such as sea stars, crabs, jellyfish, and shrimp.

Coadaptation can also limit an organisms ability to adapt to new changes in their habitat. This can lead to co- extinction. In Southern England, the large blue butterfly adapted to eat red ants. When human development reduced the red ants habitat, the local extinction of the red ant led to the local extinction of the large blue butterfly.

VOCABULARY

Term Part of Speech Definition

adapt verb to adjust to new surroundings or a new situation.

adaptation noun a modification of an organism or its parts that makes it more fit for existence. An adaptation is passed from generation to generation.

adaptive noun process in which many species develop from the same ancestral species to fill a radiation variety of different roles in the environment. 2 of 5 air pollution noun harmful chemicals in the atmosphere. algae plural noun (singular: alga) diverse group of aquatic organisms, the largest of which are seaweeds.

Arctic noun region at Earth's extreme north, encompassed by the Arctic Circle. behavioral noun way an organism acts that is passed down to the next generation. adaptation big cat noun large predators, including tigers, lions, jaguars, and leopards. carnivorous adjective meat-eating. cichlid noun spiny-finned freshwater fish. climate noun all weather conditions for a given location over a period of time. coadaptation noun the process in which organisms develop in close relationship to one another. coast noun edge of land along the sea or other large body of water. co-extinction noun the process in which the loss of one species leads to the loss of another species. continent noun one of the seven main land masses on Earth. desert noun area of land that receives no more than 25 centimeters (10 inches) of precipitation a year. development noun growth, or changing from one condition to another. diet noun foods eaten by a specific group of people or other organisms. distribute verb to divide and spread out materials. dominate verb to overpower or control. environment noun conditions that surround and influence an organism or community. eucalyptus noun tree native to Oceania. exaptation noun adaptation that developed for one purpose but is used for another. extinct adjective no longer existing. extract verb to pull out. generation noun group in a species made up of members that are roughly the same age. genetic adjective having to do with genes, inherited characteristics or heredity. habitat noun environment where an organism lives throughout the year or for shorter periods of time. hummingbird noun type of very small bird. industrial adjective having to do with factories or mechanical production.

Industrial noun change in economic and social activities, beginning in the 18th century, brought by Revolution the replacement of hand tools with machinery and mass production. inherit verb to receive from ancestors. isolation noun state of being alone or separated from a community.

3 of 5 mammal noun animal with hair that gives birth to live offspring. Female mammals produce milk to feed their offspring.

marsupial noun mammal that carries its young in a pouch on the mother's body.

migrate verb to move from one place or activity to another.

migration noun movement of a group of people or animals from one place to another.

mimic verb to copy another organism's appearance or behavior.

moth noun flying insect.

mutation noun sudden variation in one or more characteristics caused by a change in a gene or chromosome.

niche noun role and space of a species within an ecosystem.

nutrient noun substance an organism needs for energy, growth, and life.

Oceania noun region including island groups in the South Pacific.

placental noun animal (mammal) characterized by the fetus developing inside the body of the mother, mammal in an organ called the placenta.

pollen noun powdery material produced by plants, each grain of which contains a male gamete capable of fertilizing a female ovule.

pollution noun introduction of harmful materials into the environment.

resemble verb to look like.

soot noun particles produced by burning a substance such as coal, wood, or oil.

speciation noun process by which one or more populations of a species become genetically different enough to form a new species.

species noun group of similar organisms that can reproduce with each other.

structural noun way an organism physically develops that is passed down from one generation to the adaptation next.

succulent noun type of plant that has thick leaves and stems for storing water.

sympatric noun development of many similar species in a single habitat, each with a different speciation specialization.

thrive verb to develop and be successful.

unique adjective one of a kind.

urban adjective having to do with city life.

vestigial adjective having to do with a body part, or remnant of a body part, that no longer serves any useful function.

womb noun organ in which an embryo and fetus develops. Also called the uterus.

young noun offspring or children.

For Further Exploration

Articles & Profiles National Geographic News: Three High-Altitude Peoples, Three Adaptations to Thin Air 4 of 5 National Geographic News: Tetrapod Fossil Discovery—Fins to Limbs Interactives Earth Day Canada: Animal Adaptations

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