Aquatic and Land Animal Diversity

Historical Interest in Animal Diversity

How many different animals have ever existed?

Biologists have described and named more than one million species of animals, and some believe that several million to ten million more species remain to be discovered, classified, and named. Over time, deep into the Earth’s past history, even more different animals have existed, with some estimates into the hundreds of millions. The greatest numbers of animals live in the oceans, with fewer in the freshwater areas and even fewer on land.


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