The Evolutionary History of the Animal Kingdom

Early animal life (Ediacaran biota) evolved from protists during the pre-Cambrian period, which is also known as the Ediacaran period.

During the Cambrian period, the most rapid evolution of new animal species occurred, but the cause of this explosion is still unknown.

The post-Cambrian era was characterized by animal evolution and diversity where mass extinctions were followed by adaptive radiations.