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Humans haven't stopped evolving

harvardmagazine.com

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Re: Humans haven't stopped evolving

#71

Post by asdff »

adrianN wrote: post #27
lomlobon wrote: post #2

Isn't this obvious? Why on earth would it stop? I don't actually believe that 'humans stopped evolving' was ever a widespread belief among scientists. This article has gotta be lying to me.

There are a couple of species that remain essentially unchanged for the last couple million years. Why can't humans become one of them?

Nothing stops mutating. What you see with those species is that they found a zone of stability in the fitness landscape, a local optimum. They still have mutants, you just don't see them outcompeting and shifting the makeup of the overall population as the dominant form is already the most fit.

Now consider our own species and the pressures that got us to this present body plan. They just aren't there. The shark still is facing pressures that favor the hundreds of millions of years old shark morphology. Are we facing pressures that our hominid ancestors faced? Doubtful. Look at how our bodies often react when they meet the pressures of our modern society: we often become anxious, depressed, and obese. Most of our ill behaviors such as this have some survival advantage to it that just isn't getting pressured in modern society. Your constant anxiety keeping you up at night is actually saving your family clan from a lurking predator in the bush. Your lack of portion control abilities means you can eat all the fish you just caught and pack on more fat to your frame to smooth over leaner times. Today these selective advantages are seen as illnesses people see doctors to get pills for. Our bodies are so misplaced for the society we've built for ourselves. Our mind's can't even fully fit this society into a working model ourselves without missing a lot of important information. We've out ran our capabilities a long time ago in some senses with the cultural/technological evolution that overshot our own biology. We are tumbling into some new body plan I'm not sure what exactly, but things aren't in any way stable now.

Re: Humans haven't stopped evolving

#72

Post by plastic-enjoyer »

Grimblewald wrote: post #67
deepsun wrote: post #21

As far as I was taught in college, evolution never stops, but we're just too short lived to notice that. We _may_ notice some very tiny blip on timescales of several hundred years, but last really noticeable traits happened many thousands years ago. However, cultural/society/educational evolution happens much-much faster (but is also much-much weaker, can disappear on just a few weeks).

also, technology largly exists to remove the discomfort of evolutionary pressure. This doesnt mean the mutations that give rise to evolutionary changes in the population, but it does mean we've removed or mititaged many of the mechanisms which would select for specific traits. Again, we would naturally still change, but not in the the way or at the rate otger organisms continue to or at which we would sans technology…

> also, technology largly exists to remove the discomfort of evolutionary pressure.

I think this is a very limited way to view technology

Re: Humans haven't stopped evolving

#74

Post by seszett »

remarkEon wrote: post #70
seszett wrote: post #63

Earlier quoted context omitted.

All 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 ye…

Sorry, 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.

The fondamental thing here is that humans 40k years ago could live in the toundra because we can live in the toundra today, and they had a similar behaviour to ours. So they made clothes and fires for the cold, and weapons for hunting the local fauna, just like we do. And they avoided actually desolate areas because they could not live without food.

That's why the colonisation of colder areas happened at about the time of behavioural modernity. Before that, humans where anatomically modern (mostly identical to us) but did not have the cultural equipment to deal with difficult environments.

Re: Humans haven't stopped evolving

#75

Post by asdff »

margalabargala wrote: post #48
remarkEon wrote: post #34

Earlier quoted context omitted.

I guess I would need to read more of what Gould wrote. For example, did he claim that evolution in other species also stopped?

I 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.

You 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.

Re: Humans haven't stopped evolving

#76

Post by thomassmith65 »

hn_throwaway_99 wrote: post #18

Given that fertility rates are currently plummeting worldwide, the principles of natural selection would dictate that humans are currently undergoing very high selection pressure for specific traits. Basically, any genetic trait that causes people today to think "You know, I think I'm going to remain childfree" is specifically selected against, and any trait that causes people to want more children will be selected f…

Evolution is surprising and complicated enough that that might not be the full picture.

People have relatives and relatives have many genes in common.

If there are genetic traits that predispose people to remaining childless, it could wind up that populations with those genes end up with larger branches on their family tree.

It's been a while since I read the Selfish Gene, but its central point is that natural selection is about genes, not individuals.

Re: Humans haven't stopped evolving

#77

Post by saidnooneever »

chr15m wrote: post #52

Lactose tolerance is a classic example of a recently evolved trait. https://en.wikipedia.org/wiki/Lactase_persistence

I for one am glad that now people can have a healthy serving of cheese without the side effects.

Do you think we will become more and more tolerant? like with the happy people? One day maybe we can drink only milk and eat only cheese, even on the sweltering summer heat. For me those days i still struggle and sometimes reluctantly find myself reverting back to greens

Re: Humans haven't stopped evolving

#78

Post by asdff »

fhn wrote: post #6

Genetic drift is not evolution. Every single birth brings about genetic drift. Evolution is gaining or losing specific traits. Individually, humans do gain and lose traits but from an macroscopic view, those traits are just a blip. An cheetah that lose it's ability to run fast many not survive. A human that loses a some useful trait does not die(government assistance. I'm talking about the West because I can't speak…

It is far more complicated than you might gleam. Why don't cheetas run at 300mph right now? They'd catch everything in the bush right? It is a dance of course. Once you go so fast there's probably diminishing returns of what you'd additionally catch. There is also the additional caloric demands to support that top speed. Plus whatever other changes have to be made to hit that speed, e.g. maybe lighter but weaker bones. Surprising to say, a 300mph cheetah might actually be less fit than one at typical speed.

This is certainly true for humans as well. Does being faster, stronger, better vision, better hearing, necessarily mean you will beat a "worse" human for calories to survive and also mating opportunity? Nope. And that is why we aren't all 9 foot tall space jam monsters. It isn't about being a perfect specimen, but a good enough one to keep on a little longer.

Re: Humans haven't stopped evolving

#79

Post by asdff »

adrianN wrote: post #24
prologic wrote: post #7

If that's true. Why haven't we evolved into a species that doesn't harm each other or the environment?

Traditionally, harming other people and the environment has made it easier to feed your own children (or at least the children of your tribe) and have more of them.

True for plants too. Black walnut tree not only has a canopy to stymie nearby competitors, it even produces a herbicide.

Re: Humans haven't stopped evolving

#80

Post by asdff »

prologic wrote: post #7

If that's true. Why haven't we evolved into a species that doesn't harm each other or the environment?

We are parasites in a sense. Parasites are far more common than symbiotes. It is much quicker evolutionary speaking to up and have a parasitic relationship than to have the far more many step changes to actually taper that parasitic relationship into a symbiotic one that doesn't kill the host off. Doesn't bode well for ourselves though, as this implies we need to get decimated by the climate crisis to pare down our population to the small subset that gives a shit about it and also is smart enough to adapt to or slow the process, and things would only get better once this population reseeds the planet.
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