In the beardy chaos of non-parsimony, at least two theories about our human origins are competing for your attention. Let’s leave creationism out for the moment — that one is old, and has been debunked by better men. (Not to mention, its proponents do a pretty good job ridiculing their ideas themselves.) Fortunately, even while embracing evolution there is enough room for hairy theories. And what is a more engaging subject for such theories than our own evolutionary past?
Theory I: the
pig+chimp Pimp theory
Geneticist Gene McCarthy specializes in hybridization, and as such has started seeing hybrids everywhere. That happens, we all know it does. You spend the day dissecting larvae, and on your way home even the trees start to look like imaginal discs. But I digress.
The point is: Gene McCarthy, PhD, knows a hybrid when he sees one. In the mirror, for example: humans, McCarthy says, are clearly a product of hybridization. As he’s a geneticist he must have genetic evidence for this theory, right? Well, no—but he won’t let that spoil the party. Making anatomical comparisons will get you a long way, and so he listed all the traits that us humans have that can’t be found in our closest living relatives, the chimpanzees. Think earlobes, thick skins, and hairlessness. From that list it was evident who the co-parent must have been: the pig.
Yes, he’s serious, and he has a lot of ideas about how that hybridization event could have come about. Rule 34 comes to mind, and I need to change the subject now.
So let’s talk about genetics, McCarthy—you must have something, right? Why yes, he has an excuse: the original hybrids must have been backcrossed to one of the parent species, and diluted any genetic signal from the other parent. Furthermore: “Sequence differences are not necessary for anatomical differences to be present”. Well that solves that puzzle.
But what of the idea that we’re hybrids at all? For this premise, McCarthy presents the dead giveaway: human infertility. With a population over seven billion that too seems a bit of a stretch, but let’s here the man out. On his site McCarthy details all the ways in which our spermatozoa are incompetent little bastards. And the logical steps from ‘our sperm sucks’ to ‘we’re practically infertile’ to ‘must be ’cause we’re hybrids’ follow easily.
To recap: humans are infertile, we share traits with pigs, and many backcrosses will have got rid of genetic evidence. Take away Occam’s shaving implements, and the case is clear-cut. (Sadly, some popular press seems to actually think so…)
Theory II: Homo aquarius
Our surprisingly hairless skins inspired more than just a reminiscence of porcine ancestors. Together with our bipedalism, the blubbery fat under our skins, our big brains, and—only added recently—our large and empty sinuses, they provided evidence for another theory about our forefathers: they inhabited beachfront property.
The aquatic ape theory, as it is called, was first coined in the 60s by Sir Alister Clavering Hardy, marine biologist (I’m sensing a pattern here). Subsequent exploration proved an entertaining exercise: pick a human trait, and try to link it to an aquatic environment. Even better if it’s a trait that can’t be detected in fossils.
Of course you can do the same thing with basically any other hypothetical environment, but where’s the fun in that? (Actually, I was joking: there is a lot of fun in that.)
You know what: I think I get it. If you’re hairless, you don’t need a razor. It all makes sense now.
Photo by cdorobek, licensed under creative commons.