SCIENCE IN THE NEWS DAILY

The Extinction Oscillator

from Seed

... Though life's story stretches back billions of years, only its somewhat recent chapters are at all clear, and even then mostly in the ocean, where fossils are more easily formed and preserved.

Starting with the advent of abundant marine fossils about 500 million years ago, biodiversity's development over time can be seen as a rising curve; more kinds (genera) of creatures exist now than existed 500 million years ago. But closer scrutiny reveals wiggles along this steady, gradual rise.

Though they may appear minor, some of these short-term fluctuations were the most dramatic events in life's history, precipitous drops in biodiversity known as mass extinctions. ... One of the big mysteries associated with these phenomena is also a key question for life's future: Do they occur with any regularity?