this post was submitted on 11 Oct 2023

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Monthly Science Summary (lemmy.world)

submitted 1 year ago by [email protected] to c/[email protected]

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🔔 Monthly Science Summary Brief overview of major studies - stay up-to-date

🔭 Sources & Wiki: https://en.wikipedia.org/wiki/2023_in_science

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[–] [email protected] 4 points 1 year ago (1 children)

First of all, thank you! <3

Population bottleneck: I'm reading about a bottleneck 900'000 years ago. Isn't humanity only 200'000 years old?

I'm also very interested about the climate conditions and 98.7% of humans "being lost". What climate caused that dying? Does that change somehow relate to today's climate change, and does the risk of population reduction translate as well?

[–] [email protected] 3 points 1 year ago* (last edited 1 year ago)

Yes (200k–300.000), that's why it says pre-humans...we didn't arise out of nowhere, it was a continuous evolution and it seems like if those had died out we wouldn't be here. (However, that's not settled, there are substantial reasonable doubts over these results as hinted at with "While alternative explanations are possible" and elaborated in the other comments here.)

Good question, it wasn't a warming and even if it was, I don't think it can easily be translated to today's climate change. They refer to the Early-to-Middle Pleistocene Transition (not much info at that page though). If it's linked, that doesn't mean it caused it – I think people in that regard far too often think of (especially singular) causes instead of contributors within a complex interconnected set of causal factors. Maybe you're interested in this non-included paper from the same month which projects an upcoming large sudden population decline – it's just not substantiated and one can't just compare modern humans with other animal populations.

[–] [email protected] 3 points 1 year ago

That one about the human extinction risk bottleneck is far out, man

[–] [email protected] 2 points 1 year ago (2 children)

What happened to LK-99?

[–] [email protected] 3 points 1 year ago

It turned out to be an insulator if you can believe it!

[–] [email protected] 3 points 1 year ago

See the papers linked here

[–] [email protected] 2 points 1 year ago (1 children)

Wasn't the giant population drop story found to be inconclusive based on a large number of assumptions?

[–] [email protected] 5 points 1 year ago* (last edited 1 year ago) (1 children)

That's why I put "While alternative explanations are possible" there.

I didn't add it to the WP article, and nothing here suggests this to be "conclusive"...it's just really 'significant' which even skeptics of this seem to agree with. Would be interesting if you have a source for "large number of assumptions" though: that doesn't seem to be a good description what people doubting it pointed out / criticized here: https://www.nytimes.com/2023/08/31/science/human-survival-bottleneck.html I previously had something like "Some peers doubt the study but if correct, [...]" there maybe that would be clearer?

[–] [email protected] 0 points 1 year ago (1 children)

I see. I read a couple articles that mentioned that the species the original finding reports on is unidentified but assumed to be a modern human ancestor, that cumulative assumptions were made coming up with the calculations to determine that 1280 number, and that the report does not incorporate fossil evidence from other regions of the world, so the 1280 might just be a single group rather than representative of the human race, especially since it's difficult to figure out how a group that small and genetically homogenous could have effectively repopulated in health.

I didn't save the articles when I read them, but I'll look for them later and send them over if the concerns seem legitimate under scrutiny.

[–] [email protected] 1 points 1 year ago (1 children)

I don't think they were narrowing this down to one species of ancient pre-humans rather than all species thereof. The number is surely wrong, the question of the scale of magnitude is roughly accurate. Would be nice if you send it/them my way if you find them, thanks for your elaborations.

[–] [email protected] 3 points 1 year ago (1 children)

This was the one I originally read,

https://www.thejakartapost.com/culture/2023/09/16/skepticism-about-claim-human-ancestors-nearly-went-extinct.html

and there's this

https://www.scientificamerican.com/article/human-ancestors-nearly-went-extinct-900-000-years-ago/

that also specifically mentions the problem of fossils from the same time in many other parts of the world that were not examined at all or even mentioned by the original study,

This one summarizes several problems with the claim very well:

So the main problems is that the study that this number 1280 comes from focuses, very specifically on one group of fossils but pretends(or at least allows readers to make the assumption) that the results are representative of the entire fossil, archaeological and human record around the world, which they simply are not.

Another problem is that their conclusion is based on a new algorithm this team created to work out from 3,000 individuals(unknown how these individuals were chosen for this study) how many humans were left 900,000 years ago.

Even mathematically, the fact that their declared result range is only from 1270 to 1300 humans left on Earth is suspicious because it's such a narrow range for such a subjectively determined algorithm based on incomplete anthropological assumptions of a population event that occurred almost a million years ago.

The data this new study is based on is not actually new data either. They just put this old data into their new algorithm.

It is a great story and it might have even happened in the area that the tested fossils are from since population crashes and explosions do occur, but there is very little in this specific study that is scientifically rigorous or has concrete, broader ramifications for the anthropological record because of its incomplete, broad and subjective methods.

[–] [email protected] 3 points 1 year ago* (last edited 1 year ago) (1 children)

Thank you, will look into this. I had my doubts when I first heard about this but even with these sources I still think the study is significant beyond the large attention (and that itself is also a factor). I don't think there's much doubt that "The precision of the findings, though, may be a stretch" is true which doesn't invalidate the study and like a critic said "The conclusions, she says, “though intriguing, should probably be taken with some caution and explored further."

Also consider that I usually have 8 main tiles and two brief ones, the only other alternative main tiles this month were the dogxim, Y chromosome and astrocytes ones which could get summarized nicely very briefly at the bottom while this one should be included but was hard to summarize that briefly.

[–] [email protected] 2 points 1 year ago

Oh, I certainly don't mean to throw any shade on you, I was personally interested in this particular article and very wary when I saw their claim so I looked into it for a time after reading that initial popular article, but the vagueness of the research and the specific number sounded way too fishy,

It looks like all of your tiles are confirmed science in one way or the other, and after my interest in this article I remembered it was not as solidly scientific or comprehensively significant as the other subjects you post.

[–] [email protected] 0 points 1 year ago (1 children)

Ah, what is not to love about using AI to "screen" for things, while people still don't understand what it is and are using it to abuse whatever they can in any way they can.

[–] [email protected] 5 points 1 year ago

Here is the study (it both reduced workload and increased effectiveness), I don't think you understood what this was about but that's nothing to criticize with the brevity of text