Home > Encyclopedia of Science > Endangered Species

• Causes of extinction and endangerment
• How many endangered species are there?
• Words to Know
• Why are endangered species important?

An endangered species is any animal or plant species whose very survival is threatened to the point of extinction. Once extinct, a species is no longer found anywhere on Earth. Once gone, it is gone forever.

Throughout Earth's geological history species have become extinct naturally. However, in modern times species and their natural habitats are mostly threatened by human activities. Humans have already caused the extinction of many species, and large numbers of many other species are currently endangered and may soon become extinct.

Causes of...