We’ve just come back from a few glorious days in New Plymouth (arriving home before the change in weather). Had a great time tramping, walking the coastal walkway, eating yummy food – all those nice things you do, holidaying with friends. And as some of the party were driving from Paritutu to meet the rest of us at an outdoor cafe on the coastal walkway, they saw the following sign:
It’s a variant on the old "if men evolved from monkeys, why are there still monkeys", only slightly more accurate – in the sense that we are much more closely related to apes than we are to monkeys, lol. But both versions are wrong, based on a misunderstanding on the nature of evolution, and I wonder if the sign’s author would be willing to look at the evidence for the real state of affairs.
For we didn’t evolve ‘from’ modern apes. In taxonomic terms, humans are apes: placed in the primate sub-order Anthropoidea along with gorillas, chimpanzees & bonobos, orangutans, & gibbons. Morphological & DNA evidence indicates that our nearest living relatives are the chimpanzees, with whom we last shared a common ancestor around 6 million years ago. At 4.4 million years old, Ardipithecus ramidus is the oldest known hominin – & it wasn’t particularly chimp-like. Which is hardly surprising, as the ancestors of both humans and chimps/bonobos have been following separate evolutionary trajectories for all that time. As the team who discovered and described ‘Ardi’ have commented (White et al., 2009):
Perhaps the most critical single implication of Ar.ramidus is its reaffirmation of Darwin’s appreciation: humans did not evolve from chimpanzees but rather through a series of progenitors starting from a distant common ancestor that once occupied the ancient forests of the African Miocene.
T.D.White, B.Asfaw, Y.Beyene, Y.Haile-Selassie, C.Owen Lovejoy, G.Suwa & G.WoldeGabriel (2009) Ardipithecus ramidus and the palaeobiology of early hominids. Science 326: 64 (authors’ summary**) & 75-86. doi: 10.1126/science.1175802
** Teachers – the summary would be a good introductory read for your senior students.