reply to post by jiggerj
I've been studying human ancestry for years, and some day I'll get around to making a proper thread sharing my research. Till then, here's a
potentially satisfying answer to your question:
Human intelligence took millions of years to develop. We didn't eat shellfish and meat one day and the next day had intelligence. A pretty vast
time scale, in which people only lived 30 or so years, if lucky. Between predators, disease, food shortages, natural calamities, and tribal
in-fighting, there's a reason why your Pre-Man isn't alive today. Brain capacity grew very slowly, and intelligence, mostly by trial and error.
But wait, we need to clarify "human". I'll only allow Homo Sapiens to be called modern humans, and they date back to 500,000 years ago.
To get a bit more technical, your tree-hugging pre-man is often referred to as Homo Habilis. They were foragers that slept in trees, and kept to the
cover of the forest to evade predators. Rather small, and quick, they are still considered our ancestors. No they weren't monkeys, no prehensile
tail and they had opposing thumbs, and used crude tools. They date to about 2.4 million years ago, and probably used fire for warmth. Mind you, I'm
just doing a quick summary, no fancy pics or links here.
I'll toss in a dash of Homo Athropithicus, and Homo Heidelbergensis for a bit of filler.
Next comes along Homo Ergaster, master of fire usage, and toolmaking, at about 1.8 MYA, in Africa. Curiously enough, Homo Erectus had the same skill
set, but appeared to be evolving separately, at roughly the same time, in Asia.
We all know that there were no Greyhound buses back then, so the chances of contact are slim, and even so, only by foot, yet we have both Ergaster and
Erectus evolving thousands of miles apart, with both having very similar lifestyles. Quite the anomaly often overlooked by academia. Of course,
Ergaster gets credit for the "Out of Africa" Theory taught to our kids today, but Erectus was firmly established in Asia by the time Erectus got
there for a lil whoopie with the natives.
They also say that Ergaster migrated towards Europe, and evolved into Homo Neandertalis. Not me.
I'm done rambling, but in short, Homo Sapiens (you and I) trace back to 500,000 years, bellies all full of meat and shellfish, with our modern brain
capacity. The size of our cranium grows smaller the further back in time you go. They still haven't found the "missing link" between 1.3 and 1.8
million years ago, nor accounted for the sudden "final" jump in cranial capacity.
To answer your Qu more directly: all Homos were omnivorous, eating both meat and veggies, but there's not really any evidence a high protein diet
caused an increase in brain capacity over the evolution of our hominid lineage. They ate what they had handy (even each other...GASP! There's
evidence that our earliest ancestors ate the weak and wounded for nourishment), and simply tried to survive.
We're evidence they did good enough.
Fascinating topic, thanks jigger.