These familiar marine arthropods first arose about 545 million years ago in the early Cambrian and thrived throughout the world's oceans until they were wiped out in the Permian extinctions about ...

Others propose that an extinction of life just before the Cambrian opened up ecological roles, or "adaptive space," that the new forms exploited. External, ecological factors like these were ...

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 ...

This challenges the notion of abrupt events like the Cambrian Explosion and emphasizes ... of research focuses on the Late Ordovician mass extinction (LOME), which is characterized by two ...