Ancient filter-feeder was a “gentle giant”

Ancient filter-feeder was a "gentle giant"
Just 22 million years after the “Cambrian explosion,” a top predator had already evolved into a filter-feeder, able to sweep up food with sieves built into its front appendages. So what’s this got to do with the whale shark? More »

Live birth in ancient reptile

Detail from schematic diagram

Classroom Activity Page: The fossil of a plesiosaur, which was a large, dangerous predator of the seas between 200 and 85 million years ago, showed strong evidence of being pregnant. Evidence for pregnancy included the location of the unborn plesiosaur, its size, and the fact that its bones were not fully hardened, or ossified. The find helps flesh out the evolutionary transition between laying eggs and live birth. More »

Breaking the Cambrian barrier

Breaking the Cambrian barrier

Darwin thought life had to predate the Cambrian era, and yet there was no evidence. In 1953, a Wisconsin geologist saw fossils aged almost 2 billion years. Now, life has been discovered in rocks from 3.5 billion years. What was life like, and how do we recognize it? More »