Human Evolution: By Natural or Artificial Selection? Part Two

If you’re reading this, I’d be 99.99% sure you’re human. That being the case, you probably are aware that humans evolved from our primate ancestors, most likely the chimpanzees, starting many eons of time ago in deep, darkest, equatorial Africa. From that point of origin, humans colonized the globe, including whatever part of Planet Earth you currently call home. That’s the be-all-and-end-all of the origin, evolution and colonization of and by the human race. Well, I think there are some flies in that ointment, especially the bit about our evolution.

Continued from yesterday’s blog…

Though there are some limited advantages to standing upright (apart from freeing up two arms to do things with like grab forbidden fruit slightly higher up in the trees)  – you can see farther; wade slightly deeper waters, in general a bipedal stance comes at a considerable cost. Two limbs now have to take up all the body weight instead of four legs (or six - if you’re a bug; or eight – if you’re a spider). If one of those two limbs fails, you’re in deep poo. However, survival is more probable if you have four (or six or eight) legs and one fails.

Further, if you’re bipedal, your centre of gravity shifts, making you way more prone to losing your balance and falling over. Also, bipedal animals tend to run slower than a quadrupedal one. Most dogs whose backbones are at my knee height or more, and cats, can easily outrun me. The same goes for alligators, even with their splayed out limbs when they’re going full tilt. The upshot of all of that is that in the animal kingdom, only birds (and their ancestors, the theropod bipedal saurischian dinosaurs) are (or were) bipedal – for fairly obvious reasons. Two of their four ‘legs’ have evolved for flying. Humans have no such fallback since we can’t flap our arms and fly.

You don’t have to be a professional zoologist or expert in anatomy to realise that any creature going from a quadrupedal gait to a bipedal one has to have a massive amount of anatomical alterations to its basic structures. Bone and muscle lengths and widths will change; there must be alterations to the various joints, nearly all muscle attachments to the bones will alter; support structures for many internal organs will need rethinking, etc. Imagine the anatomical changes you’d have to make in your dog or cat or horse for that animal to walk in the same manner you do; imagine the changes that would have to be made in your anatomy for you to walk like a dog, cat or horse. It’s a big ask of natural selection to go from quadrupedal to bipedal without some clearly defined survival advantage(s); perhaps not so much of an ask if the shift is artificial selection; guided by an intelligence using bioengineering or genetic engineering techniques.

Now various animals can, and do, for brief periods, stand upright, say prairie dogs, chipmunks, bears, etc. Some animals can be taught to briefly stand up like circus elephants. Kangaroos, wallabies and related are usually bipedal, but they hop, not walk or run. Not even our primate relations routinely walk around on two legs although many can and do so for brief periods.

I think the advantages of a bipedal way of posture and locomotion are overstated, otherwise way more animals would have evolved that posture; you’d expect our cats and dogs to not so much as sit-up and beg but stand-up and beg for special treats. Out of millions and millions of vertebrate species that have existed over the past 300 or so million years of geologic history, only a relative tiny handful have adopted the bipedal mode of lifestyle. It’s not proved to be exactly an evolutionary success story unlike the more universal backbones and rib cages and skulls all vertebrates have.

Overall, in the biological scheme of things, we’re not just a little bit more advanced in a bipedal way, we’re WAY MORE advanced. The question is, why? Again, why are humans so obviously bipedal? And if we’re not so inclined to be bipedal by natural selection, perhaps then we’ve been so evolutionary inclined by artificial selection – by the ‘gods’ to free up our upper limbs, a useful trait if the ‘gods’ put us to work.

Now humans are smart. We’re top of the ‘food chain’ when it comes to IQ. We have very large brains relative to our body size. We have very complex brains. But all that size and complexity has a cost. An infant’s head has to be pretty soft and squishy and malleable and hence very vulnerable in order to fit through the birth canal, and even then it’s a struggle and a pretty dicey part of an infant’s and mother’s life.

Another high IQ evolutionary drawback is that it takes a lot of energy from the food we consume to power the brain and brain functions/activity, including thinking and processing thoughts. Higher IQ translates into the need to consume more calories. In the ancient world that took additional time to find or harvest food; in the modern era, it costs you more, say pound for pound to feed you vis-à-vis your lower IQ companion animals. 

Now intelligence, the ability to figure things out, must have a degree of natural survival value. Cats and dogs and pigs and many wild birds and dolphins and the humble octopus and our primate cousins aren’t dumb. Again, unlike the universal vertebrate backbone, rib cages, and skulls millions of vertebrate species have (or had) only one has excelled – top-of-the-pops – in IQ. BUT, we’re not just a little bit more advanced in the IQ department. We’re massively more advanced.

One might expect, based on natural selection, that if our average IQ was 100, perhaps our primate relations might have an average IQ of say, 90. That’s not the case. Most of the mammalian kingdom is clustered around a relatively narrow range of IQ way lower than ours. A dog isn’t a 100 times smarter than a cat or vice versa. But, humans are a 100 times smarter than our mammalian (and all other vertebrate) relations. Why? What natural evolutionary pressure did we face than thousands of other vertebrates, especially mammals, and especially, especially the primates, didn’t? Some human-only evolutionary pressure drove up our IQ levels to such extraordinary heights, but what evolutionary pressure?

You’d be hard pressed to think of any other terrestrial bipedal, high IQ species that could build the pyramids – in fact the answer is no other terrestrial species could.  Again, why were humans so blessed? And if we’re not so blessed with a high IQ by natural selection, then perhaps it must be by artificial selection; selection by, or genetic bioengineering by, the ‘gods’?

Moving on down the line, as each step in the ‘gods’ enforced artificial evolution of humans was achieved, slightly more upright posture; slightly higher average IQ, the previous lot – the less advanced hominoid species – were left to their own fate – extinction. There’s a lot of extinct hominoid species (for example, Homo habilis, Gigantopithecus or the Neanderthals) that are evolutionary links separating us from our primate ancestors, most probably chimpanzees, now our closest modern kissing cousins. 

When the ‘gods’ had at last achieved a reasonable facsimile of their objective, they gave us the gifts of knowledge (the basics anyway) and helped kick-started us on our road to civilized society. At some point or other we probably – ungrateful twerps that we tend to be – pissed them off and they packed their bags and left, perhaps leaving behind a token presence (UFOs) to monitor us to ensure we don’t ever become a threat to them and reverse the roles of slave and master.

To be continued...