Extinction

In biology and ecology, extinction is the ceasing of existence of species or a group of species. The moment of extinction is generally considered to be the death of the last individual of that species. Extinction is usually a natural phenomenon; it is estimated that more than 99.9% of all species that have ever lived are now extinct. Species become extinct when they are no longer able to survive in changing conditions or against superior competition. Currently, environmental groups and some governments are concerned with the extinction of species due to human intervention, and are attempting to combat further extinctions. Humans can cause extinction of a species through over harvesting, pollution, and destruction of habitat, introduction of new predators and food competitors and other influences. According to the World Conservation Union (WCU, also known as IUCN), 784 extinctions have been recorded since the year 1500. Endangered species are species that are in danger of becoming extinct; several organizations attempt to preserve recognized endangered species through a variety of conservation programs.

More about this: Wikipedia or Dino Extinction