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• Evolutionary Essentials
In less than thirty million years, a mere instant in Earth’s vast history, nearly all the major animal groups living today first appeared. From the Cambrian through the Ordovician Periods, life continued to diversify and grow in the Earth’s shallow oceans.
Among several events during these periods, a few key developments occurred that affected the evolution of life in the coming eras:
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The development of skeletons—hard shells and plates evolved and provided a framework for bodies that could now grow larger.
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The development of vertebrate animals, which eventually led to the evolution of the largest animals on Earth. |
Continue to The Evolution of Skeletons. >>
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