Our Human Ancestors Very Nearly Went Extinct 900,000 Years Ago, Genetics Suggest
Our Human Ancestors Very Nearly Went Extinct 900,000 Years Ago, Genetics Suggest
A study proposes that the population that gave rise to modern humans may have been reduced to roughly 1,300 reproducing individuals
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Does this mean that at one point, there were 1,300 humans that were the only population around that could have given rise eventually to today's population?
Or, that there were 1,300 individuals that happened to give rise to today's population, and a whole bunch more that didn't, but that would have if those specific 1,300 weren't around?
I wasn't able to tell from this article, and maybe the original study is a little more clever in its analysis, but there's no clear indication of which it is in this article -- which makes me think that maybe it's #2 and the person that wrote it just hasn't realized that #1 and #2 are very different statements.
(Or, maybe #1 gets more clicks, and they're well aware of that.)
It's #1, but there's plenty of room for error, and the exact number the researchers came up with was 1280. That's just what the genetic sampling says. They did the analysis on the samples that they have. It's not like they could travel back in time and take a genetic sample of every populated area in the world, so it isn't a precise number. However, they would expect more variation if there were more of the species actually living at that time. The number they came up with is useful, though. It tells you there weren't a lot of people alive to reproduce at that time and they know there was a higher population of the species before that time. Also, outside of this article, the same evidence is cited along with how it is known that there was probably a huge population collapse thanks to other pieces of evidence. Anyway, plenty of specialists in multiple fields can confirm that environmental conditions were very harsh, making it very difficult for most forms of life to survive. So, the number, as outrageously small as it might seem, is pretty close to reality.
What's their evidence that it's #1, and not #2? I read the links but I still don't see a reason why. I'm not saying it is #2, just that as you said:
They did the analysis on the samples that they have. It’s not like they could travel back in time and take a genetic sample
Yes, which means that the only populations that are "visible" to this technique are the humans that left descendants to the modern day. Maybe there were other populations that didn't leave descendants to the modern day, specifically because of competition with other humans (but which would have survived, if not for the competition for their same niche).
Again, I'm not saying that that did happen. Just that it instantly jumps out based on a cursory reading of this that it sounds pretty possible, and I'm curious to see if there's an explanation for why it's not possible.
Also, outside of this article, the same evidence is cited along with how it is known that there was probably a huge population collapse thanks to other pieces of evidence.
I'm sure there was a huge population collapse; as I understand it, that's an established fact based on a sudden absence of humans in the fossil record. But, it's a very different statement to say "there was a population collapse" versus the statement "there was a population collapse down to 1,280 individuals." One is not proof of the other.
When I said "They did the analysis on the samples that they have" I was referring to the samples from 900,000 years ago that they used for comparison. The modern-day samples are bountiful and random enough. You should verify that for yourself by reading the article that was originally published in Science, linked to in the article. When you say "I'm sure there was a huge population collapse; as I understand it, that's an established fact" you are kind of putting a huge amount of faith in theories. While, yes, it's very certain, it is the best conclusion to be drawn from a lot of evidence. The only way to be sure would to have been there to observe it. That's not possible. Perhaps you should reconsider the relevance of this thought of yours with regard to the researchers' goals:
the only populations that are “visible” to this technique are the humans that left descendants to the modern day. Maybe there were other populations that didn’t leave descendants to the modern day
That's the whole point of the study, you see, to see how many people survived to reproduce in the past. The ones that did not survive to reproduce are irrelevant. They died. They are not the ancestors of modern-day humans because they died before they could reproduce and start a lineage. We didn't inherit those people's DNA because they did not live long enough to pass it on to us. The article in fact underllines this, stating that the findings are a number of people who survived and reproduced. We did not descend from the people who died and did not reproduce. Dead people don't make babies.
Also, maybe you're just tired.
My brother - you've got no call to be being rude to me.
My assertion is that the premise "the current world population is all descended from a bottlenecked population of 1,300" does not imply that "if those 1,300 people hadn't made it, humans wouldn't be here." If human populations didn't compete significantly with each other, then one would follow pretty strongly from the other, but if you're going to argue that, I think the neanderthals and denisovans would strongly disagree with you.
I did click on the link to the Science article, but I don't feel like paying $30 for it. Hence, me asking for more information. Me pointing out my assertion up above, or wanting to know more about the study to see whether that premise is all that they've demonstrated, or that conclusion is actually one that they're arguing, or etc, doesn't mean you need to be talking to me all condescending. Honestly, even if I was just saying something stupid, as you seem to think I am, you'd still be just being a dick by sending this type of message. IDK man. Best of luck to you.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” ― Bertrand Russell
I wasn't being rude. I was honestly confused by your question and thought that you were asking for info beyond what the article in the OP is about because it was late at night. You are still insisting on a research question that is outside the scope of the article. Along the way, you are editing what you originally asked. I'm also not arguing with you. I was merely regurgitating what the article was about. You asked "is it X or Y?" Now, you're talking about something that's interesting, but is not a question the researchers asked of the data. You're also attacking me. If you have a problem with the research presented in the OP, your argument is with the scientists that did the work, not me.
Yeah maybe you’re just a bit too confident for your level of intelligence.
Not really. The researchers weren't looking for people that died and didn't reproduce.