extinction

In recent decades, the populations of many vulture species declined sharply and are now acutely threatened with extinction.

According to basic ecological theory, two different species cannot exist on the same limiting resource -- the better competitor is expected to drive the other to extinction.

There, he had gained a reputation as a turnaround artist by saving the school from the brink of extinction.

Hunted nearly to extinction during 20th century whaling, the Antarctic blue whale, the world's largest animal, went from a population size of roughly 200,000 to little more than 300.

Navaornis lived approximately 80 million years ago in what is now Brazil, before the mass extinction event that killed all non-avian dinosaurs.