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If evolution is real why are there still monkeys?

How can we be descended from monkeys if there are monkeys around today?

With all the 'monkeying around' that can go on in the playground or even in the office it seems we could easily be directly descended from monkeys, but our evolutionary relationship is actually much more distant.

"This is a question often encountered by evolutionary biologists," says Dr Paul Willis, palaeontologist and Director of RIAus.

"But the question itself reveals a couple of fundamental misunderstandings about evolution and how it operates", he says.

Firstly, humans did not evolve from monkeys. Instead, monkeys and humans share a common ancestor from which both evolved around 25 million years ago.

This evolutionary relationship is supported both by the fossil record and DNA analysis. A 2007 study showed that humans and rhesus monkeys share about 93% of their DNA. Based on the similarities and differences between the two types of DNA, scientists have estimated that humans and rhesus monkeys diverged from their common ancestor 25 million years ago.

Similarly, the fossil record has identified ancestors common to both humans and monkeys, such as an as yet unnamed primate fossil from Myanmar found in 2009 and dated as living around 37 million years ago.

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Our closer cousins

Humans are actually more closely related to chimpanzees and other apes, but DNA evidence again shows that we didn't evolve from them. Chimps and humans share between 98 to 99% of DNA suggesting that we shared a common ancestor around 6 million years ago.

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Evolution is not linear

"The idea of sharing a common ancestor leads to the second major misunderstanding inherent in the question," says Dr Willis, "that evolution is a linear process where one species evolves into another."

Evolution is really a branching process where one species can give rise to two or more species.

"The fallacy of linear evolution is most clearly illustrated by the analogy of asking; how can I share common grandparents with my cousins if my cousins and my grandparents are still alive?," says Dr Willis.

"The answer is of course that your grandparents had more than one child and they each went off and started their own families creating new branches of your own family tree."

The same thing happens in evolutionary families. A species can split into two or more descendant species and they can split again and again across the generations.

Dr Paul Willis is the Director of RiAus and formerly a presenter on ABC TV's Catalyst program.