Extinction is the complete disappearance of a species from the earth.
This happens when a species cannot adapt to new environmental conditions. Environmental changes, mass destruction and competition between species are the main causes of extinction. An example of an environmental change would be the damage that humans have done by growth of cities and population. Natural disasters play a major part in the destruction of species. Floods, volcanic eruptions, earthquakes, and major changes in temperatures have all contributed to the extinction of many different species in the past.