3 min read The Cambrian period, part of the Paleozoic era ... including many major animal groups alive today. Among them were the chordates, to which vertebrates (animals with backbones) such ...

Researchers think there are now around 7.7 million animal species living on Earth, with thousands more discovered every year.

All animal evolution for the last half billion ... Recent research suggests that the period prior to the Cambrian explosion saw the gradual evolution of a "genetic tool kit" of genes that govern ...

This discovery provides more insight into how animals evolved from single ... of that latter phenomenon is the Cambrian Explosion—the geologic period some 530 million years ago when Earth ...

Arthropods were the most diverse animal group in the Cambrian period and the Ordovician period that followed. The 452-million-year-old limestone slab shown here captures an Ordovician menagerie ...

“The emergence of paired nerve cords likely facilitated greater movement coordination, particularly in segmented animals. During the Precambrian-Cambrian transition, changes in the nervous and ...