This graph plots extinction rates of marine animal families over the last 600 million years. The shaded band indicates the normal range of extinction rates, known as "background extinction." ...

The fossil record presents many challenges, but the problem may be approached with combinatoric analysis, and graph and network theories. This paper is a brief introduction to the aspects of those ...

Concerns over the extinction risk of the monarch led the Center for Biological ... Monarch butterfly population graph by Tierra Curry, Center for Biological Diversity. This image is available for ...