Australia: The Land Where Time Began

A biography of the Australian continent 

Cambrian Explosion - Fossils of the Explosion with Bilateral Body Plans

During the Cambrian explosion the bilaterians, that had circulatory systems, and mostly fluid skeletons, entered the fossil record in large numbers. Larger animals generally fossilise more easily, and, as the authors¹ point out, part of the explosive appearance of these fossils represents a significant increase in metazoan body size that is independent, in many different lineages, as suggested by the clear linkage between fluid skeletons, blood-vascular systems and larger body sizes. Stiff integuments and mineralised skeletons evolved in response to the need for more structured support for larger bodies, though skeletons must have also provided a degree of protection from predators, as well as broadening the bilaterians taphonomic window.

Sources & Further reading

1. Erwin, Douglas H., & Valentine, James W., 2013, The Cambrian Explosion: The Construction of Animal Biodiversity, Roberts & Co., Greenwood Village, Colorado