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Adaptation is the ability of animals, including human beings, and plants to adjust to their environment. Living things adjust to changes in their environment in various ways. Changes in the environment may involve other living organisms or non-living things, such as the weather, that are a part of surroundings.

Some forms of life adapt more easily than others. For example, people can adjust to many different environments. They live in all kinds of climates, ranging from the tropics to the Arctic. Human beings are generalized. That is, the human body allows people to adapt more easily to different environments. But such living beings as mosquitoes and bamboo plants are more specialized. Because of their physical makeup, they can live only in a rather warm, wet climate.

Most living things die when they cannot adjust to their environment. Many kinds of plants and animals that once lived on the earth have become extinct. For example, giant reptiles called dinosaurs roamed the earth millions of years ago. But then, the swamps they lived in dried up, and the climate and food changed. The dinosaurs failed to adjust to these changes and died out. But certain dinosaurs are the ancestors of reptiles.

Living beings may adapt to changes in environment in two ways. A population (group of the same kind of organism) may adapt through evolution over many generations. It usually occurs gradually over long periods of time – thousands or millions of years. Or an organism may adapt within its own lifetime by adjusting its behavior or body chemistry in some way. Changes in behaviour are caused by such external conditions as weather, soil and the food supply.