Human Evolution: the evidence evolves!

I see there are new fossil finds in Morocco which have been reported on the BBC. Here is the Nature Letter that reports the new find. What were modern humans up to prior to the flowering of human civilisation that left no mark prior to, lets say, ten thousand years ago? Why the large brains? Why the capacity for complex communication? Why the gap of over a quarter of a million years before the burst into human civilisation?

103 thoughts on “Human Evolution: the evidence evolves!”

  1. phoodoo

    keiths:
    Alan,

    You asked for evidence because you didn’t realize that you already had it. It was just a mistake.It’s not the end of the world.

    You’re making this far harder for yourself than it needs to be.

    Evidence isn’t- “It is, therefore it is evidence why it is.” The answer is assuming its own correctness. You are wrong.

    Maybe the high metabolic cost is why humans have to eat more things, but it doesn’t help them survive better than what they replaced. Maybe they wanted to have larger brains. Maybe they were destined for larger brains. Maybe humans are the worst adapted animals on the planet. There are a dozen assumptions in your conclusion that are nothing but assertions.

  2. Alan FoxAlan Fox Post author

    Kantian Naturalist: As for why cognitive evolution seems to have plateaued (about 300,000 years ago) — I took this to be one of your questions — one constraint worth noting is the size of the birth canal.

    If human infants were born with larger brains, they couldn’t pass through the birth canal (or do with even greater difficulty). If the birth canal were larger, that would interfere with efficient walking and running. If infants were born at an earlier stage of development, they would be even more prone to infection, other systems wouldn’t be developed as much, and so forth.

    In other words, the constraints of primate embryology and the constraints of hominid locomotion together put a hard ceiling on how large hominid brains can be.

    That makes a great deal of sense.

  3. phoodoo

    Kn,

    Can you explain what being plastic to ones environment means? Is there a gene for being “plastic” ? How does one obtain this “plastic” condition, through a random mutation? Mutation to what exactly?

    Unless, this can be explained, the concept is meaningless.

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