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 ...

Lampreys and hagfish are these fishes' living descendants. The archaic sponge reef-dwellers of the Cambrian gave way to ... There is also evidence that the first primitive plants began to appear ...

It has long been suspected that the sparseness of the pre-Cambrian fossil record reflects these two problems. First, organisms may not have sequestered and secreted much in the way of fossilizable ...

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 ...

"Dinosaurs laid eggs, the fish that first crawled out of the sea laid eggs, and the weird articulated monsters that swam in the warm shallow seas of the Cambrian Period 500 million years ago also ...

The history of life on Earth dates back more than 500 million years, when complex-structured organisms emerged during the ...