A simplified evolutionary tree of primate relationships showing the placement of Darwinius in relationship to other groups. From Williams et al., 2010.
The study of human origins can be a paradoxical thing. We know that we evolved from ancestral apes (and, in fact, are just one peculiar kind of ape), yet we are obsessed with the features that distinguish us from our close relatives. The ‘big questions’ in evolutionary anthropology, from why we stand upright to how our brains became so large, are all centered around distancing us from a prehistoric ape baseline. Despite our preoccupation with ‘human uniqueness’, however, many of our traits are extremely ancient, and they can be traced back much further than the seven million years or so that hominins have existed.
As acknowledged by paleontologists Blythe Williams, Richard Kay, and Christopher Kirk (who confirmed that Darwinius was only a very distant relative of ours last week) in a new PNAS paper, ‘human evolution did not begin 6-8 million years ago with the phylogenetic split between the chimpanzee and human lineages.’ It is not as if the first hominins appeared out of nothing and began an upward march to us. Instead we know that we could hypothetically trace our lineage all the way back to the last common ancestor of all life on earth, and any point we chose to stop along that ‘unbroken thread‘ could tell us quite a bit about our history. In the case of the present review, Williams, Kay, and Kirk pick up with the origin of anthropoid primates.
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