Is the Lamarckian theory of evolution making a come-back?
Actually, to a very limited extent, yes.
If you are going to step on my little joke, you should at least include a link.
My favorite hypothesis is that we lost it as part of our adaption for persistence hunting.
You need to go beyond watching Animal Planet. The aquatic ape hypothesis doesn’t argue for the existence of mermaids. It just suggests that we’re old beach apes.
From your link:
(Asking anyone)
How does bipedalism increase endurance?
I’m glad to hear this was just a joke.
Yup, that’s am interesting one too. Plus it looks like it’s possible it arose the same time as fire. Last I heard, the earliest definite fire site is 250KYA, but there’s other evidence that cooking may date as far back as 2MYA – but very unlikely more that that for reasons I don’t remember.
It suggests more than that, but I wasn’t referring to that hypothesis in the original post. I was referring to this one:
First of all, “Tarzan” is a fictional modern human, not a human ancestor. Secondly, no old-World monkey has a prehensile tail, so it’s not like “we lost” one. Thirdly, no ape has a tail of any kind, and yet non-human apes do not have head hair like modern humans.
Ask Cro-Magnon Man. Better yet, ask Eoanthropus dawsonii. 
We became less adept in trees when we lost our prehensile feet, rather than our tails. And that happened after we had already descended to the ground.
But Morgainelf obviously meant the hypothesis facetiously.
No, not really. By far, most aquatic ape proponents don’t take these hominins beyond the coasts. I personally don’t see any logic in us ever having been seafaring apes, not untill the invention of boating, at least (which is the last few thousand years versus our perhaps five million year of evolution since a mutual ancestor with chimps). An ape adapting to coasts in tropical Africa is not at all unreasonable, I’d say. Paleontology has suggested that all elephants (including mastodons and mammoths) had early ancestors that went through a similar aquatic stage, e.g. moeritherium living similarly to extant hippos 37mya.
But in terms of long head hair, you’d need to distinguish between ethnicities. Consensus is, that anatomically modern humans derive from East Africa, and people there don’t have the long straight hair, but rather its heavily curled up (as “afro”). If by selective pressure, this could’ve been an adaptation to have a still layer of air between the sunrays and the scalp, to avoid excessive heating of the brain. Regardless of why we lost the rest of our fur, aquatic reason or no, we still would’ve needed to protect the scalp from the sun. And the notion of swimming babies hanging onto mama’s head hair is not impossible, other apes’ offspring hangs onto their mother’s fur, and James Cook reported seeting aboriginal women bathing with their babies hanging in their hair exactly in that fashion.
The straight hair of Asians and Europeans, possibly emerging in e.g. the mesolithic, could either have been by genetic drift, or if by selective pressure, as an adaptation to continuous precipitation of Asia and Europe coupled with there less solar radiation. Straight hair would then allow the head hair to lead rain and show away from the scalp and dry faster to conversely avoid excessive cooling of the brain.
It’s been a while since I read Born to Run, but I recall that quadrupedal respiration gets a boost from a sort of ‘bellows’ affect - as the back legs move, they provide some ‘free’ energy to the diaphragm/lungs.
However, that also limits the breathing rate to the running speed - one breath per gallop, basically. If an animal needs to pant to cool down/recover, it must stop running, and our persistence runner can bash it with a rock.
Hopefully I haven’t made a complete mess of that explanation. I don’t recall the book went into much detail (and I don’t think McDougall is a biologist, so he was probably just summarizing something he read), so the above is at best a third hand explanation.
I guess it wasn’t.
Odd, I was thinking of an article I read in 2012. I’ll look for it on my other computer tomorrow, if I remember.
Thank you very much.