A new report in the journal Nature has interesting implications for human evolution.  

Homo habilis, a clearly bipedal (walking on two legs) potential human ancestor, had been known from about 2.4 to 1.8 mya (million years ago.)  During that time, the "robust" australopithecines also appeared in Africa.

In short, a find of Homo habilis extends the temporal range of the species from about 1.8 mya to 1.44 mya.  A nearby Homo erectus skull dated at 1.55 mya, shows the two species coexisted for some time ... even though they shared characteristics that advanced them beyond the Australopithecus stage, particularly in terms of increasing relative brain size.  Keep in mind that another hominin (bipedal primate), Australopithecus bosiei, was around East Africa at the same time.  That is a lot of bipeds dividing up the ecological niches, and will have interesting implications about how our ancestors, and their cousins, evolved.

News of the report can be found here.  "But wait, there's more!"

Unfortunately,  the sensationalism around the find has once again resulted in a lot of misunderstanding about the nature of evolution in general, and human evolution in particular.  Even worse, some of the misunderstanding has been initiated by some of my colleagues who should have known better.

At issue is a fundamental aspect of evolution -- the relationship of "parent" species and "daughter" species.  Evolutionary biologists have long known that species can diverge into new species in a number of ways.  But until 1949, human evolution was viewed as an exception ... a ladder of evolution.

What happened in 1949?  John Robinson and Robert Broom discovered, at the South African fossil site of Swartkrans, that two hominin species existed at the same time.   Later, at Olduvai Gorge, the same phenomenon was revealed.  So the human family tree was shown to have many branches.  Indeed, with finds from the past 20 years or so, it is a very bushy tree.

So we've known for some time that there was no direct route to humans.  The road had a lot of twists and turns, and dead ends.  With all that evolutionary meandering, can a "parent" species and a "daughter" species still coexist.  Yes!  Of course!

In Sparing Nature I note that the most frequent question I get is this:  "If we evolved from apes, why are there still apes?"  To crop from the book-length version of my answer, the point is simply that the evolution of life creates diversity. It is not A-->B-->C, otherwise there would be NO diversity.  The amoeba-to-human chain would be straight, and we'd be all that was left.  It obviously didn't work that way.

Okay, so there have to have been divergences.  Does that mean that an ancestor can coexist with it's descendant?  Yes! Of course!

I illustrate this to my creationist friends this way:  If mammals were descended from reptiles, should there still be reptiles?  On a species scale it works the same way:  If dogs evolved from wolves, should there still be wolves.  In both cases, evolutionary theory says "yes ... sometimes, but not always."  Species go extinct.  Most species that ever lived are extinct.

  Whether or not a species lives to coexist, or diverge further from it's descendant, is a matter of chance, coincidence, and chaos.  In The Riddled Chain, I refer to this as the "ox-bow lake effect."  Just as rivers leave old meanders behind as ox-bow lakes, so does evolution leave behind species that persist for a while, but eventually make no further contribution to the flow of evolution.

So the new discovery does not change the theory of evolution, and confirms the directions of human evolutionary understanding that began in 1949.

  Creationism 

  Intelligent Design