There was evidence that as much as 75,000 years ago, the human population experienced a sudden drop in genetic population, a "bottleneck" catastrophe. Was the supereruption of the volcano Toba to blame? Or did different shifts in climate, those that gave Africa repeated periods of drought, really do the job? Whatever the culprit, this bottleneck changed the destiny of human history. As a result, one race of people has a far smaller genetic distinction from another than two chimpanzees in one same troop.

Let us assume that, in an alternate timeline, the bottleneck catastrophe happened at a later date, preferably during the Younger Dryas climate chaos 11,000 years ago. At that time, there was a four-to-thirteen-degree-Fahrenheit drop in global temperature at a span of 1200 years, too quick for ice age plant and animal species to deal with. It most certainly brought an end to the Clovis culture.

Delay the bottleneck to the Younger Dryas, and how much of a population growth would we have seen between 75,000 and 11,000 years ago? Would human history, preferably history taking place during the Bronze Age, be reset on an earlier date? Would a higher genetic diversity give humans significant differences in their appearances and anatomies?

  • $\begingroup$ shifting time will not change biodiversity - 10000 peoples are 10000 peoples. I mean if we talking about same bottleneck $\endgroup$ – MolbOrg Jun 29 '16 at 22:28
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    $\begingroup$ I'm unqualified to answer this, but I don't understand @MolbOrg's comment. Given mutation, evolution, etc., wouldn't the 75,000 year later descendants of a starting pool of 10,000 people be more bio-diverse than the 11,000 year later descendants of that same pool? $\endgroup$ – Henry Taylor Jun 29 '16 at 22:40
  • $\begingroup$ @HenryTaylor I see your point, and it is valid, just everything is more interesting, but it's clear what u mean. Point of my comment was denial of OP's 11000 later equals higher genetic diversity today. Answering only this his sub question - will make big answer. Mitochondrial Eve was born 100-200k year ago, Y-Adam 200-300k years ago (altrough there are other numbers) Eve(140k), Adam(60-90k). But only their descendants survived today. $\endgroup$ – MolbOrg Jun 30 '16 at 0:15
  • $\begingroup$ But thinking we all started only form their gene pools is totally wrong. Their genes mixed with rest of population (like redhair) and it's believed that bottleneck was 10k ppl or even less. Each man had Y-chromosome from adam, but the rest of genes was arbitrary genes available from population pool at that moment from previous generations. Roughly speaking we started from maximum diversity available for 10k peoples. Probably lesser diversity is only because of limited number of peoples survived in time of bottleneck, not because of time it happened. $\endgroup$ – MolbOrg Jun 30 '16 at 0:17
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    $\begingroup$ This question is most definitely too broad. $\endgroup$ – Aify Jun 30 '16 at 0:41