FEATURE ARTICLE
The Origin of Animal Body Plans
Recent fossil finds and new insights into animal development are providing fresh perspectives on the riddle of the explosion of animals during the Early Cambrian
Douglas Erwin, James Valentine, David Jablonski
For its first 3 billion years on earth, life was no larger or more
sophisticated than a single cell. All of that changed when almost
600 million years ago new, multicellular life forms appear in the
fossil record. Starting with simple soft-bodied creatures this
evolutionary innovation culminates in the "Cambrian
explosion," a burst of biological creativity unprecedented in
earth's history. The Cambrian epoch saw the creation of hundreds of
life forms stranger than anything humanly imaginable. Many of these
animals are now extinct, but those that remained established all of
the basic bodyplans of all animals that evolved since. Until
recently, it was difficult to understand the biological mechanisms
underlying the creation and evolution of body architectures, much
less establish lines of descendence. But new discoveries in
molecular biology and development, as well as new ways of analyzing
genetic relationships is helping scientists reconstruct the earliest
chapters in the history of life on earth.
Go to Article