Extinction Is Inevitable
Over its 4.5-billion-year history, the Earth has been home to a diverse range of plant and animal life. A study of the fossil record uncovers everything from tiny trilobites to enormous dinosaurs. Some fossilized animals and plants bear little resemblance to anything living on Earth today. Others share an uncanny resemblance with their modern descendants.
Regardless of their appearance, the one thing all these fossilized creatures have in common is that they are extinct. Earth has experienced an ongoing cycle of extinction and development throughout its history. Most of these extinctions are separated by 100 million years or so.
The difference between past extinctions and the one most scientists agree is happening today is the cause. Previous extinctions came about because of factors that life on Earth had little control over. But most of the research suggests that an ongoing mass extinction taking place now would have its roots in human activity.