“Today we’re calling Homo erectus outside of Africa Homo ergaster,” they’ll say and you accept that and it’s all well and good. But then the next paper will turn around and say “Homo erectus in Africa is called H.rodesiensis, in China it’s called H. erectus.”
You begin to scratch your head, somewhat confused. And you’re not the only one. It’s gotten so bad some papers are actively refusing to state what species the specimens their examining because of the confusion associated with doing so. “Our find is called AL 288–1 and it doesn’t look like KNM-WT”
But of course, having to memorise a bunch of fossil identification numbers isn’t much better. So you cry out in frustration “how can you people not make up your minds?!?”
EvoAnth turns back to you and says “evolution.” They may also add “dumbass” depending upon what side of the bed they woke up on that morning. Richard Dawkins, renowned evolutionary biologist, often talks about how if one had all the skulls of a rabbit and its ancestors and lined them up it would be hard to pick out when it “stops being a rabbit.” Yet if one takes a skull from each endpoint they are clearly different species.
This is the problem with human evolution. Take, for example, Homo heidelbergensis transitioning into Homo neanderthalensis. At each end are two clearly different species, with H. heidelbergensis being taller, having a smaller brain, differently shaped teeth and jaws and taller skull with a less protruding (or prognathic, if you want to use the fancy sciency word) than H. neanderthalensis.
But if you take specimens from the middle of this transition it becomes a lot harder to differentiate between them. For example, the skeletons from Atapuerca in Spain come from just before Neanderthals evolved. Whilst some neanderthal traits are emerging, they have always been classified as H. heidelbergensis because, well, they’re still H. heidelbergensis. But new research has found yet another neanderthal trait – their teeth. Indeed, it would seem that most of the specimens have teeth more commonly found in H. neanderthalensis despite the fact that the rest of them still pretty much looks like H. heidelbergensis.
In fact, some of them appear to have teeth more neanderthal than later neanderthals, as if the whole issue isn’t confusing enough already.
It would seem 500,000 years ago Europe was full of multiple lineages, all emerging, evolving and co-existing from/with one another. It’s evolution in action and boy does it make it hard for one to come to a consensus on what to call them.
I mean, do we call these toothy critters H. heidelbergensis or neanderthals…or something new? And if we go for something new, where do we decide they and and heidel/neanderthal begins? That’s a few dozen possiblities right there, all from a discovery that a few teeth look like somebody else’s teeth.
For another example, take Homo habilis. It’s a loosely defined species so it’s obvious there are a few extra ones within it, but what are they?
If you take two opposite points you can get H. rudolfensis and H. gautengensis. That might not seem like much but these species seem rather close to H. helmei and H. rhodesiensis, which are in turn very similar to H. erectus.
It’s one vast chain of species that are all so similar that it’s difficult to disentangle them all and identifying where one stops and another starts is night impossible. Once again, it’s evolution and it makes life very difficult.
So next time an evolutionary anthropologist uses a strange definition of a species please have a little patience.
And the next time a creationist says there are no transitional forms, punch them. There are they make life hell.
|Martinón-Torres, M., Bermúdez de Castro, J., Gómez-Robles, A., Prado-Simón, L., & Arsuaga, J. (2012). Morphological description and comparison of the dental remains from Atapuerca-Sima de los Huesos site (Spain) Journal of Human Evolution, 62 (1), 7-58 DOI: 10.1016/j.jhevol.2011.08.007|
|Wood, B., & Leakey, M. (2011). The Omo-Turkana Basin Fossil Hominins and Their Contribution to Our Understanding of Human Evolution in Africa Evolutionary Anthropology: Issues, News, and Reviews, 20 (6), 264-292 DOI: 10.1002/evan.20335|