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by PittleyDunkin 544 days ago
Am I missing something? Surely Europe is the same continent as Asia. Why wouldn't people just walk over? It seems reasonable to assume that if evidence exists on one side of the continent that it'd imply existence on the other side, too. If anything you'd need a theory why they failed to spread to formulate interesting discussion!
1 comments
hackinthebochs 544 days ago
The Steppes are a natural barrier between East and West until the point where technology caught up to make it passable.
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PittleyDunkin 544 days ago
Well we have human ancestors on both sides of that barrier, so clearly it's not insurmountable in absolute terms, either from taking the souther route or migrating with herds or some other thing I haven't thought about (I'm not sure waterways would get you the whole way, but it'd get you from the urals to either side). The question is why this would pose a barrier to some populations and not others.

EDIT: also, I forgot that a lot of the steppe is forested. Surely that would make it significantly less of a barrier.

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hackinthebochs 544 days ago
No terrain is insurmountable considering chance and a hundred thousand years. The question is how likely will any given group be able to pass through and flourish on the other side? We have many examples of isolated human populations on islands or across inhospitable barriers that it shouldn't be surprising to find isolated populations on either side of the Eurasian continent. Off the top of my head, Australian aboriginals, the Andamanese and New Guinea islanders are examples of isolated populations with essentially no gene flow between larger populations over 10s of thousands of years. Even the fact that we talk about how many populations ultimately left Africa in prehistory implies there must have been some barrier to overcome.

> also, I forgot that a lot of the steppe is forested. Surely that would make it significantly less of a barrier.

Also consider the ice age and how that affected the degree to which Eurasia was hospitable.

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anonymousDan 544 days ago
What exactly do you mean by the Steppes? I thought this referred to a grassland region so can't see how it would constitute a barrier.
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hackinthebochs 544 days ago
Yes, its a continent-spanning grassland. But humans don't eat grass. Sourcing water is also a problem. It's inhospitable to humans without some reliable means of turning grass into nutrition. If we're talking about early humans it would be a significant barrier.
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