The end of the Cambrian saw a series of mass extinctions during which many shell-dwelling brachiopods and other animals went extinct. The trilobites also suffered heavy losses.

First, organisms may not have sequestered ... Others propose that an extinction of life just before the Cambrian opened up ecological roles, or "adaptive space," that the new forms exploited.

Still, they became extinct more than 10,000 years ... shallow seas about 505 million years ago during the Cambrian period, hunting small organisms. The unusual anatomy that it evolved to have ...

dramatically. It was the time of the Cambrian Explosion, an eruption of life when Earth’s very first animals began appearing in the fossil record — the ancestors of all major animal groups ...

Was the extinction absolute ... difference in how those wormy creatures turned. By the early Cambrian, burrowing animals became more systematic in their searches for food, as well as more muscled.

For over a century, the Cambrian arthropod Helmetia expansa remained a mystery. Discovered by paleontologist Charles ...

The next step was for multicellular organisms to concentrate their light-sensitive cells into a single location. Patches of photosensitive cells were probably common long before the Cambrian ...

First, organisms may not have sequestered ... Others propose that an extinction of life just before the Cambrian opened up ecological roles, or "adaptive space," that the new forms exploited.