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I have definitely run into the belief that humans aren’t evolving anymore (though not among scientists). I think people with an incomplete understanding of evol
by derektank 3mo ago
I have definitely run into the belief that humans aren’t evolving anymore (though not among scientists). I think people with an incomplete understanding of evolution look around, see most human beings survive to adulthood, and assume that there must be no more evolutionary pressures on us (perhaps with the phrase “survival of the fittest” tinging around inside their head). I honestly don’t blame anyone who hasn’t been exposed to the concept of e.g. sexual selection for making the assumption.
- delichon 3mo agoThere's been no biological change in humans in 40,000 or 50,000 years. Everything we call culture and civilization we’ve built with the same body and brain. -- Stephen Jay Gould, "The Spice of Life", 2000 Gould was an evolutionary biologist and Harvard professor, and one of the most prominent popularizers of evolution since Darwin, but somehow believed that it doesn't apply to modern humans.
- remarkEon 3mo agoThat's such an extreme claim. It defies common sense. You'd have to proclaim that there was some event that _stopped_ evolution in humans, universally. How is that even possible? Especially 50k years ago. I'd be a little more forgiving if the claim was that evolution stopped in, say, 1999.
- RajT88 3mo agoRather a lot more things about human genomic history are known today compared to 2000. Discoveries about being able to process lactose and when those genes evolved all were after 2000, for example. Does it excuse Gould for making such bold claims? You have to decide I guess. That is a lot fuzzier.
- remarkEon 3mo agoI guess I would need to read more of what Gould wrote. For example, did he claim that evolution in other species also stopped?
- margalabargala 3mo agoI think the claim that humans stopped evolving is an uncharitable reading. Another would be, 50k years is such a narrow window that evolution cannot be observed across it.
- t0mpr1c3 3mo agoIt's not an uncharitable reading if Gould stated his claim unequivocably. Your alternative claim is just factually wrong. The population frequency of an allele under selection pressure can change within a few generations. For example the HbS allele, that confers both sickle cell trait and malaria resistance, became less common among Africans transported as slaves to regions where malaria was not endemic.
- asdff 3mo agoYou can observe evolution on much narrower timescales. People were following how covid was evolving after all. Evolution just means some changes to dna. Even identical twin children have some differences between them.
- johnthewise 3mo agoIt's more of a function of selection pressure applied to genes per unit time based on some environmental factor, so you'd expect to observe less evolution in narrower timescales simply because it takes few decades for humans to pass on genes versus bacteria or viruses. In the same fashion, if some gene pool is locally optimal(?) against the environmental pressures, it may just stop evolving meaningfully. E.g, If male baldness were reversed easily with a pill or something, the environmental pressure to select those genes would decrease rapidly.
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- retrac 3mo agoEmphasis should be placed on "everything we call culture and civilization". There is a thought experiment that might help. Imagine we had a time machine, and no scruples, and we could go back and pluck babies from the past to experimentally raise them in modern American families. I'm pretty sure Gould would have argued that babies from 40k years ago would grow up to be behaviourally indistinguishable from modern humans.
- remarkEon 3mo agoWell, evaluating the nature of this thought experiment reveals what you actually believe about human evolution and development. I find it extremely hard to believe that someone from 40k years ago would be indistinguishable from humans today. Believing this requires you to imagine that there are no genetic selection pressures for things like intelligence, behavior, physical ability ... 40k years ago had Earth as an almost entirely different planet. Europe was frozen for most of the year, for example. There were no trees. Very, very hard to believe that people born back then could grow up to sit in front of a laptop today.
- seszett 3mo agoAll we know basically is that their skeletons are undistinguishable from ours, with a brain the same size as ours (slightly later on average iirc) and what they left, tools and paintings, look just like what we can do as well (behavioural modernity, thought to arise some time between -100 000 and -40 000). You can find it hard to believe, but I think most people in that field agree that humans from the last 40 000 years would grow up as modern humans without problems.
- remarkEon 3mo agoSorry, you're claiming that people who lived in a desolate tundra 40k years ago are the same as you and me. Can you be more specific? There's both a hardware and firmware element to this. Perhaps the hardware element is transferable.
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- inigyou 3mo agoSounds like they just meant evolution takes longer than that? To some degree it's true. We have all sorts of variable parameters that are probably different from back then (eg. Average height) but we still have the same body shape, etc
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- Jach 3mo agoOne should not read or pay much attention to anything Gould wrote or said. (http://cogweb.ucla.edu/Debate/CEP_Gould.html http://cogweb.ucla.edu/Debate/CEP_Gould.html) The amount of damage Gould has done offsets any positives. It's not just even being wrong, indeed you can charitably read that quote as being almost correct (the phrase is "anatomically modern human"); the worst thing he's done is probably to mischaracterize the rest of the field as scientists believing things they don't (or haven't for many decades before he ever tried to address them).
- padjo 3mo agoCountering the nonsense prevalent in a lot of evolutionary psychology counts as a big positive in my book.
- wahern 3mo agoDespite being so famous, I feel like his ideas haven't aged well. His ideas were contentious yet embraced by popular science writers, and there's never been a reckoning.
- knowaveragejoe 3mo agoFor the average person considering this question it also goes without saying that it's hard to grasp the time scales involved.