No One Knows Why Humans Can Walk
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First, what I'm calling the Geo-Fermi Paradox - why are we the only intelligent animal on Earth?
Sure, it has advantages - but other animals would gain those advantages too. So why didn't they become intelligent (or, at least, more intelligent) too?
Sure, there was climate-change in Africa that rewarded adaptivity - but why didn't all animals in the region become intelligent (or, at least, more intelligent)?
This article has a good argument for bipelalism (due to forests becoming plains). And an interesting argument for stone throwing (and not available to bipeds like ostriches and emus).
Throwing rewards spatial reasoning, providing an evolutionary pressure It's not clear to me that this would lead to intelligence - but maybe it did. (OTOH bonobos, chimpanzees, gorillas, orang-utans, and capuchins throw too https://wikipedia.org/wiki/Projectile_use_by_non-human_organ...).
So it might be more like "we are the ones that remain", but yeah, either variant is a spin on the old weak anthropic principle, which is never quite satisfying.
> fire-cooking, rock-throwing domesticating niche
Just knowing if that was the evolutionary pressure along the path would be enough for me (even if it could have been another ape or a corvid or whatever - or maybe they are on that path now?)
BTW Matt Ridley has the theory that division of labour (trade enabling specialization) was the gradient.
Notably there is some speculation that Neanderthals were of equal or similar intelligence to early humans
Natural food was was less calorie dense back then. I wonder if we reached a point where we could consume the most calories per pound of our own body weight, and never looked back.
The process is not stuck in time. If we disappeared, another ape (or some other animal) might get where we are eventually, through some other path.
Are other animals not intelligent? Are you sure we are intelligent?
I guess that the difference between apes and humans would be minuscule to the outside observer.
Because humans took over that "being intelligent" niche and outcompeted everyone else who tried to capitalize on intelligence.
Speaking in Venture Capitalists language, humans "sucked the oxygen from the room".
So, isn't bipedalism simply the energetically better way of locomotion for the primate body plan (look at other primates, they semi-walk on their lower limbs, only balancing with their hands - but they are not great at running and live mostly on trees so climbing is more important there)?
I've found the most beneficial exercise for me is hours-long walks/rides, well within my comfort zone - much lower than the heart-rate reccommended. Partly because it's enjoyable.
I've seen numerous speculation on the finger wrinkles, possibly an adaption.... or possibly just happenstance. Sure today's fingers prune significantly, not sure they would do the same if heavily callused by a decade or two of hunter gathering for all your food. In any case it's not unique to humans, macaques have similar and I suspect it's noticed because they bathe. Couldn't find any information on other primates.
[edit for minor spelling/grammar tweaks]
The bulk of our hair is on the top of the head - the only place that would be burnt by the sun if you stay all day standing in shallow waters.
The shape of our nose (nostrils directed down) are made convenient to stand vertically without getting water into airways.
What is the picture of a paradise? A beach with a white sand, sun shining, clear blue water, lots of palm trees near the coast. This is because its our natural habitat. Not deep forests, not savannah. It's tropical beach!
If I was to be left alone and naked on an inhabited piece of land I would definitely choose a tropical beach out of all untouched locations on the planet, because it is the most likely place where I would be able to survive.
BTW Apparently out of favour, but I like the aquatic ape theory too. Shellfish are high protein, support brain development; coastal settlements found.
Fur combined with skin oils is a great insulator as it is a hydrophobic surface in which air bubbles get trapped proving very good insulation.
Our skin is very porous and thin and gets soggy very quickly in water which makes it less grippy and weakens it.
We also have terrible physique for swimming (hence why we need to develop complex swimming techniques instead of just paddling) just to put it into perspective a deer can swim as fast as 15 mph, a polar bear can swim at about 7 mph for 10 hours the fastest human swimmer can swim at around 5mph and that’s for a 100m sprint, we have fairly poor buoyancy and a very weak diving reflex compared to other mammals and like most apes we are actually quite terrified of water naturally.
Our vision is also severely impacted by water, especially salt water and we have a very water ingress unfriendly nose-ear system.
The whole aquatic ape theory doesn’t make any sense it’s almost as crazy as the chimp fucked a pig theory.
Like seriously take pretty much any other non ape mammal and you’ll discover that they are so much better at swimming than humans that they might as well be fish compared to us even those who don’t look like they should be able to swim at all.
Like freaking mice have been observed swimming for 3 days straight.
I also like the idea that consuming fish and shellfish contributed to our brain transformation, given omega 3 is highly beneficial for healthy brains.
Shellfish have pretty much no omega 3 in them, cold water fish do which are hardly easy to catch in shallow waters.
Nuts and seed however are much richer in Omega 3 than most fish.
Again the aquatic ape theory does not stand up to any level of scrutiny pretty much any claim it makes can be disproven or attributed to other much likely factors it is pseudoscience in its purest form.
The truth is that AAH doesn't match the fossil record (or the fact that apes have been observed swimming even in the wild since it was proposed, the fact that in captivity apes develop similar or higher subcutaneous fat deposits to modern humans, and the average ape still has a higher body fat percentage than a human athlete).
Australopithecus afarensis (Lucy) circa 3.5Ma was bipedal, Australopithecus anamensis 4.2 Ma was bipedal as well albeit with primitive features for the upper body, Ardipithecus ramidus which is about 4.5 Ma had both habitual tree and bipedal adaptations (e.g. could stand upright and likely walk pretty well but had opposable big toes for grabbing at branches).
The earliest clear signs of modern bipedalism (as in a walking gait similar to that of modern humans) is around 3.7 Ma and it's not a skeleton but rather the Laetoli Footprints in Tanzania.
For the most part we had direct and "in-direct" ancestors for about 5 million years with varying degree of bipedalism, we likely haven't been eating seafood at for more than 200-300,000 based on remains found at various sites.
Lastly Shellfish which would be the easiest food source for the shallow water Aquatic Ape is one of the most common food allergies with 3-4% of the population suffering from it, and it causes Anaphylaxis in almost every case unlike other allergies which vary in severity. If we count in seafood allergy in general which includes finned fish then about 2.5% of the adult population suffers from it.
It's quite unlikely that a common food source that impacted our evolutionary path so greatly would have a fairly deadly allergy tied to it.
On the other hand humans are not allergic to mammalian meat (unless they are bitten by a few species of a tick and develop and Alpha-gal allergy) at all, and only in extremely rare cases are allergic to poultry.
It's fun to think of the ramifications though. Are/can we look for human fossils in the right places? How much of our history is potentially under water and not African caves. Did it help spur fire usage so that we could safely eat fish? Did it influence the out of Africa migration which was mostly coastal (we got to Australia before Europe)?
It probably didn't affect our evolution much but I suspect a lot more of our pre-history was spent at least on the shallow ocean than we have evidence for.
Of course, it's still possible that those who could walk upright could throw stones better I suppose? So the fundamental idea of tool use has merit. But the tools would have been far more primitive than spears and bows. And still, the walking would likely have happened before the stone throwing, so there's still a little uncertainty even with the idea that it helped us with primitive tool use.
I think it's probably more that you could see predators better and get a head start for the tree. But I have no data to back that up, it's just my gut hunch.
Feels like they are implying something here ... Can't figure out if I'm offended
And look at us now
But quite a lot of birds walk, and a lot more of their dinosarian relatives did. Ostriches and emus favor it, when they are not running. Faster than we can.
Orangutans do it too, though not very often.
There's a lot to be said for parallel/convergent evolution, but it's certainly not hard & fast rule.
Genesis 1:26-27 ESV
Then God said, "Let us make man in our image, after our likeness. And let them have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth and over every creeping thing that creeps on the earth." [27] So God created man in his own image, in the image of God he created him; male and female he created them.
Reference: https://www.jw.org/en/bible-teachings/questions/god-omnipres...
I'm not sure if that's what he/she meant or not.
That the God of the Bible doesn't look like a man or woman is clear from the below verse:
"Therefore, watch yourselves closely—since you did not see any form on the day [God] spoke to you...that you may not act corruptly by making for yourselves any carved image having the form of any symbol, the representation of male or female." - Deuteronomy 4:15-16
So, the injunction against creating an image that looked like a man or woman to represent God, would indicate that he does not physically look like a man or a woman.
That's no doubt why it says, "you saw now form"
God the Father is clearly not in a physical form throughout the Bible. I believe that's why "graven images" are forbidden in the Ten Commandments, as they'd mislead people into thinking of him as a physical being. God the Father as depicted in the Bible is closer to an omnipresent, omniscient mind that runs the universe as a simulation inside itself and occasionally talks to entities inside the simulation through avatars, dreams, and visions.
Rather, I think "in his own image" there refers to sapience, self-awareness, and creativity - what is called elsewhere in Scripture "the breath of God".
Much of what makes the Incarnation of Christ so meaningful is precisely that God is made man, with hands, feet, head, and heart. He is Emannuel, "God with us," come to debug and repair the system we broke from within, knowing our suffering and giving us the knowledge and strength to help repair it ourselves.
That all loses a lot of its meaning if God the Father is just a big man on a throne in a cloud somewhere (an image that I have never found anywhere in the text and am puzzled as to where it came from). He was always just one of us if that's the case.
So, yeah. Despite apparently sharing your fundamental beliefs about the world, I think you're way off base about why humans walk.
Another "in his image" interpretation I've heard is that it's something of a mistranslation. That it's more like "in his imagination" or "he imagined/conceived us" than "we look like him." That's the one I've always gone by, but I like your take too.
At the beginning of this post (starting from Begin digression), there's an exploration of anthropomorphic metaphors that might interest you: http://www.wall.org/~aron/blog/god-and-time-iv-impassibility...
Also, have you read The Everlasting Man by G.K. Chesterton? It has some ideas found in your comment regarding the Incarnation and it is overall a fun read.
I have read several of Chesterton's books, but I don't think I have ever gotten around to The Everlasting Man. Someday.
Also, Dawkins manages to stick to the facts and evidence and almost entirely avoid the religion bashing in this book, making it much more approachable for religious folks.
That refers to free will (which humans have, but animals do not), not physical shape.