An adaptation is a feature of an organism which, under specific environmental conditions, bestows upon that organism an advantage in the competition to survive and reproduce known as natural selection. Adaptations can be anatomical, physiological, or behavioural traits, with the only stipulation being that they contribute to an organism's ability to survive and reproduce. Throughout the history of life on Earth, plants and animals have evolved a wide range of adaptations in order to improve their ability to inhabit the diverse ecosystems around the world.
Some plants have adapted to living in environments with nitrogen-poor soil by luring, capturing, and digesting prey. Nitrogen is required for plants to synthesise protein, so these plants digest the protein from their prey rather than synthesise it on their own. Probably the best-known carnivorous bog plant is the Venus flytrap, native to a small region within 100 miles of Wilmington, North Carolina. The traps of the Venus flytrap are actually modified leaves that contain nectar to lure insects. When an insect lands on the leaf and touches one of three trigger hairs on either side of the trap, the leaf folds shut. The interlocking teeth of the leaf prevent the insect's escape as digestive fluids break down all but the prey's exoskeleton.
Some plants have adapted to life on Earth by invading the tissue of other plants to extract food, minerals, and water. Over 3,000 species of parasitic plants are known to exist worldwide, and each species of parasite usually has a narrow range of host species that it infects. Mistletoe, traditionally used for holiday decorations, is one species of plant parasite. Mistletoe seeds have evolved the ability to germinate on host trees, where their roots are adapted to penetrate into the wood to extract water and other nutrients.
Plants living in deserts require particular adaptations to deal with intense amounts of heat and sunlight. Some species have developed dense leaf hairs to deflect harmful sunlight and prevent it from damaging the plant's chlorophyll or DNA. The Peruvian old man cactus is so named because the highly modified leaves look like waves of silvery hair. Other plants, such as the vertical leaf senecio, orient their leaves vertically to create a smaller surface area struck by direct light.
Mimicry in animals is an adaptation that confuses prey, increasing the chance of survival of that particular organism. Mimicry comes in two forms: Batesian mimicry and Mullerian mimicry. Batesian mimicry occurs when an organism mimics another organism that is more highly protected than the mimic. For example, the harmless Baja Mountain kingsnake from Arizona shares the same red and black colouration as the poisonous coral snake. Predators leave the Baja Mountain kingsnake alone because they are afraid of the coral snake. Mullerian mimicry occurs when both the model and the mimic are well protected. Queen butterflies and monarch butterflies share the same colouration, and both taste terrible to predators. If a predator eats a monarch, it will stay away from a queen butterfly and vice versa.
Beavers have adapted behavioural traits that have widespread effects on ecosystems; in this they are much like humans. Beavers have evolved the habit of building dams, the primary natural method of establishing wetlands. The wetlands, ponds, and meadows formed by the construction of beaver dams increases the biodiversity of ecosystems and improves the overall quality of the environment.