Evolutionary origins of animal biodiversity

September 3, 2018, University of Bristol

A new study by an international team of researchers, led by scientists from the University of Bristol, has revealed the origins and evolution of animal body plans.

Animals evolved from unicellular ancestors, diversifying into thirty or forty distinct anatomical designs. When and how these designs emerged has been the focus of debate, both on the speed of evolutionary change, and the mechanisms by which fundamental evolutionary change occurs.

Did animal body plans emerge over eons of gradual evolutionary change, as Darwin suggested, or did these designs emerge in an explosive diversification episode during the Cambrian Period, about half a billion years ago?

The research team tackled this question by exhaustively compiling the presence and absence of thousands of features from all living animal groups.

Professor Philip Donoghue, from the University of Bristol's School of Earth Sciences, said: "This allowed us to create a 'shape space' for animal body plans, quantifying their similarities and differences.

"Our results show that fundamental evolutionary change was not limited to an early burst of evolutionary experimentation. Animal designs have continued to evolve to the present day—not gradually as Darwin predicted—but in fits and starts, episodically through their evolutionary history."

Read more at: