From a strictly reproductive standpoint, that’s more or less true. However, it could well be said that a child with grandparents stands a higher chance of survival and success in life, as they have more time to teach and to rear children while the younger adults are off fighting bears and lions. So, children that have ancestors who live longer may reproduce more, leading to them and their children living longer.
As we are not in the pit, i am not free to discuss this further.
One side effect of our complex global economy is that people in developed countries who do have children, tend to put that off for a while, often into their 30’s. Plus, where age 12 or so used to be adulthood (Oy vey!) today the timeline of nurturing for a child ( think college funding, living in parents’ basements, etc.) is well past that. Plus, yes, the grandparent hypothesis is alive and well. Indeed , it is one of the explanations for the development of menopause.
Also, as very old traditional societies indicate, the elders were repositories of knowledge to pass on to the children in the days before books and google.
And while letting humans with diabetes survive and reproduce is only human, the point is it creates a subpopulation even more dependent on these more fragile global supply chains. And as recent current events in the USA demonstrate, if the economy is in turmoil, supply chains are irrelevant if the population which needs something cannot afford it, whether it’s insulin or other meds or food.
And to circle back to the OP - in the last century or so, we’ve changed drastically from a society where parents had several children, but many died of diseases before reaching adulthood - to one where parents have very few children, but those receive treatments that make them very much able to survive. Some of it is vaccination, some of it is other public health measures that reduce the risk of even contacting and contracting diseases. The current issue with RSV and other respiratory diseases is a demonstration of how susceptible humans can be with a short break from such contact, a side effect too of crowded living conditions (crowded compared to ancient societies).
I’m just saying, be aware of the risk involved in what we do.
I am not an expert in this field, but I have both an undergraduate and graduate degree in physical anthropology.
I cannot think of a way that anyone or anything can stop evolution through natural selection. It’s a natural process that just happens. Even forcing all humans to marry (hetero) and forcing all couples to have two natural children (impossible by itself, but can be imagined) AND then rinsing and repeating so everyone has an absolutely identical number of descendants would not stop natural selection from doing its thing.
Yes it would. The key to evolution is natural selection. If any genetics can reproduce equally, then I’m not sure what you call it, but I assume you mean that random genetic mutations (like diabetes, Huntington, hemophilia, etc. Or smarter, stronger, taller, shorter) will occur and spread randomly through the population thus changing what the genetic makeup of the population actually is. (And of course, some of these mutations may make it impossible to have the requisite 2 children and pass on that mutation, so still -selection.) This is precisely the “genetic dilution” was meant by the lecturer I mentioned.
So I think we can all agree - changes can, will, and do happen in genetic makeup.
Maybe it’s a good thing for our species that so many people have genetic weaknesses. That way, if a catastrophe occurs, a larger percentage of the population will die off quickly, leaving more resources for the survivors.
It’s good that we have a lot of genetic variation. People with a tendency towards diabetes are more likely to successfully carry a fetus when there’s not enough food. I think everyone knows that carrying a gene for some genetic blood disorders can protect against malaria. A lot of "genetic weaknesses"are strengths in certain environments.
I think the OP is broadly correct, but we just have to be careful a little about phrasing and what inferences we draw.
Our Homo ancestors lost much of their fur living in a (semi-) arid climate (probably…thermoregulation is the most popular theory AIUI), then were able to spread to other environments thanks to fashioning various forms of clothing.
If, for whatever reason, our ancestors failed to invent clothing, and somehow all else being equal then yes; I’d expect we still would have been able to spread to other environments thanks to our other advantages, but there would have been a selective pressure for humans to become more hairy, or adapt in other ways to the cold.
But this is true about many of our unique features, from our ball and socket shoulder joint (great for throwing missiles but comparatively weak in hand to hand scraps) and bipedal stance.
And it’s not really a weakness; fur, for example, would be a disadvantage to us in many ways vs hairless + clothes.
True, but I think there is still good reason to put sentient species in a special bracket when it comes to natural selection.
I know people don’t like to do this, because the meme of “We think we’re special, but we’re not” is super-popular, but there are some situations where sentience does make a significant difference, and this is a key one.
Because firstly we can often change our environment much quicker than life or death or mating choices can keep up with. We are constantly moving the goalposts.
And then you have “artificial” selection; the deliberate choices of our culture / society including now the choices made by the AIs that we have developed. Perhaps soon we’ll be able to choose our appearance, or that of our children. And we’ll be able to choose whether these traits are passed on or not.
Are we going to consider all of this part of natural selection? If so, the term natural selection has just become very broad. Forget all the stuff about inheritance of traits better suited to an environment, now it just means “whatever events result in any differences in gene frequencies, directly or indirectly”.
I think it’s simpler to define natural selection in the current way, the way that makes sense for almost every species on the planet, and tread carefully when considering the concept in the context of a sentient species.
While it’s mostly ‘oh that’s interesting’ level of supposition, a recent CNN article brought this thread to mind:
https://www.cnn.com/2023/01/05/europe/bear-skins-prehistoric-clothing-scn/index.html
Sort version, cut patterns on bones showed signs that animals were having their fur removed for clothing as far back as 300,000 years ago. Which is kinda cool, we don’t get a lot of organic evidence for such things that far back.
But it raised a side note that gave me a chuckle. We’ve talked about whether humans would have evolved if we didn’t have clothing, but if you just read the title “Did humans wearing clothes prevent evolution” the answer according to the article is a resounding no, because it enabled it!
Genetic studies of lice indicate that clothing lice diverged from their human head louse ancestors at least 83,000 years ago and possibly as early as 170,000 years ago, which suggests humans were wearing clothes before major migrations out of Africa.
So, sure, it wasn’t human evolution being enabled, but still… 
Can’t have it both ways - humans wore fur in northern Germany but humans were wearing furs before major migrations out of Africa. Actual implication seems to be that even with earlier minor migrations out of Africa, the migrants were smart enough to acquire and wear furs and had the tools to get them.
Despite the pretty illustrations, it seems to me the logical way to wear furs, especially before tanning was perfected, was with the fur on the inside, creating a trapped air layer. So presumably tanning and came along about 170,000 years ago or so, which would be when humans had furs that lasted longer than winter season before rotting and clothing lice had a chance to stay alive year round.
From what I recall reading, the loss of fur was related to our marathon abilities - running after game for hours required less “fur” and far better sweat glands to shed the heat. We have one of the better-developed thermal regulation systems based on sweat. Yes, clothing meant that we never evolved (Selected for) a need to re-insulate in other colder climates.
I would think the term for that is genetic drft. Genetic changes imply evolution if hey affect reproduction rates and general survival. Changes that are neutral in the current circumstances are drift. Whether they are advantageous or not if circumstances (environment) change - then it would become evolution.
I haven’t read this whole wonderful thread, so if I’ve been ninja’d…
Anyway, Far Side cartoon about a cavepeople party. Everyone is wearing furs except one guy. Someone is talking to him, “I’m telling you straight Oog, nobody is naked anymore.”
Oh come now, I wasn’t holding up the rigor of the statements, as written it’s pop sci at best, and even in the quotes from the scholarly work, there is a metric ton of supposition. I just felt it was a good fit for the thread, and once again wanted to point out that ‘preventing evolution’ relies on a seriously flawed understanding of what evolution -IS-.
Yes, I can agree with that.
I feel that the desire to classify every change in gene frequencies as natural selection can sometimes be misleading. Particularly when it’s motivated by a desire to make a philosophical point about humans not being special.
At the least, we can accept that there are different “flavors” of natural selection…an asteroid strike wiping out all life on a continent is quite different from a gene being selected for because it aids in camouflage.
NB: None of that’s addressed at you, md-2000, I am just explaining where I am coming from.
The depictions we have seen in textbooks and other illustrations of primitive man are almost all completely wrong. A cave man, (I’ll just use that name), would not have had a fur skirt around his waist with the fur on the outside. The fur would have been worn on the inside and the rawhide on the outside. And they wouldn’t have been so modest that they needed to cover up their waist. The pictures of cave man with a bare chest and a fur skirt are silly if you think about it.
The early fur robe would be worn around the upper torso to protect and warm the vital organs. Before any sort of tailoring was done just wrapping a fur around your upper torso would be an obvious improvemnt.
Even fairly recently when Lewis and Clark were living with the local tribes on the NW coast of Oregon they commented on the natives not wearing pants at all. They wore upper garments and large hats woven out of cedar bark and no pants. Thier culture revolved around the waterways and use of canoes. They were in and out of their canoes and the water so often that wearing lower garments made no sense.