Evolution

4. The fifth mass extinction, around 65 million years ago, which caused the extinction of the dinosaurs.
7. The first of the "Big Five" mass extinctions, which occurred about 444 million years ago and resulted in the loss of 86% of species.
10. The process through which species adapt to their environment, with advantageous traits becoming more common in a population.
12. The second major mass extinction event, around 360 million years ago, with a 75% species loss.

1. The process by which new species evolve from existing ones.
2. Known as "The Great Dying," the third mass extinction event, approximately 250 million years ago, with a 96% species loss.
3. The type of extinction with steady, natural loss of species over long periods, typically without catastrophic events.
5. The fourth mass extinction, about 200 million years ago, resulting in an 80% species loss.
6. Bird Species that had gone extinct within 200 years of discovery
8. A comprehensive inventory of the global conservation status of species.
9. An extinction with a rapid and widespread loss of a large number of species in a relatively short period.
11. The complete loss of all members of a species.
13. units that are used to describe rate of background extinction