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.

This significant assemblage of the early Cambrian organisms, known as the Chengjiang ... the largest mass extinction event ever killed off 81% of marine animals and 75% of land vertebrates.

While many scientists think that they subsequently evolved into new forms of animals that continued into the Cambrian period, others say that they were wiped out by extinction. 800 mya ...

The archaic sponge reef-dwellers of the Cambrian gave way to bryozoans—tiny, group-living animals that built coral ... in the second largest mass extinction of all time, wiping out at least ...