Evolution of Human Hair - AMNH SciCafe
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- Опубликовано: 9 июн 2023
- Why do humans have the bulk of our hair on our heads, not our bodies? This important evolutionary question is central to the work of Tina Lasisi, a biological anthropologist at the University of Southern California.
In this SciCafe, Lasisi will tease out the mysteries behind why humans have scalp hair and why we may have developed different hair textures as we’ve evolved.
#anthropology #humanevolution #hair
SciCafe: At the Root of Human Hair is presented in collaboration with The Leakey Foundation.
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This was good. She's a great speaker. Well done
She is very eloquent and has an energizing vibe; she would make a great lecturer. Also, the audience was really appreciative and didn't let her humor fall flat, so kudos to them as well! Very fun and informative overall. Thanks for sharing.
So cool. I loved the twist about sweat!
Cool talk! I'm curious as to why humans evolved to *shed* hair and regrow it in a cycle, as opposed to it just stopping growing, like adult teeth.
She's iconic. She should have a show
She does! Check out "Why Am I Like This?" on our RUclips BFF channel, @PBSTerra: ruclips.net/video/y7S8tAK-74k/видео.html
this was wonderful, i thoroughly enjoyed it! however, i'm curious if sexual selection is a secondary evolutionary reason for the hair on our heads? What i mean is why are we capable of growing more than 18 feet of hair, no other animal, to my knowledge, does that, if it was all about thermal regulation wouldnt our hair only be a few inches long, isnt having hair that long actually counterproductive to thermal regulation?
I feel sexual selection must play a role in this as well.
Consider how quickly the genes for blonde hair became common, and not so very long ago either.
@@ericvulgate i think color has more to do with uv absorption, its why you see more red heads where you dont get as much sun, but i think ridiculous length is like a bird of paradise thing like why can some people grow their 3 times the length of their bodies all it does is get in the way, it makes hygiene more difficult especially before running water i'm like the opposite of an expert but i would really like an expert to explain it to me
Is there a second part to this? I totally feel that all the important part is missing. Like:
1. Phylogenetic evidence for tight curl being the ancestral phenotype in humans (at least Homo sapiens).
2. Genetic evidence for Neanderthal keratine (hair-texture related) genetics being selected for in the Asian-plus (OoA) subpopulation (but surely not all branches, those with tropical geography seem to generally retain the ancestral phenotype). This is IMO the source of straight hair in modern humans: not strict linear evolution but Neanderthal admiture.
You should make a second part
@@fullup91 - I'm totally useless doing videos, presentations and such, sorry. Also I would have other priorities.
Where did the original populations of homo sapiens evolve? Africa?
@@chesterdamolester6990 - Yes, Africa. All the evidence points to the Upper Nile region. Mitochondrial DNA clearly points to that area (Sudans, Ethiopia, Uganda, etc.) and the oldest true H. sapiens we have are from Southern Ethiiopia (Omo 1).
Y-DNA, once we remove the very rare A0 and A00, which are from Central-West Africa but almost certainly represent introgression by closely related "archaics", is also from the Upper Nile region (A1 and descendants, which are almost all modern human patrilineages).
If you ever read or hear that there is older H. sapiens from Morocco, that's incorrect: they are a closely related "archaic" branch, as there are others in Tanzania or even Ethiopia itself (Omo 2 for example).
The material (tools) evidence (MSA or African Middle Paleolithic, quite diverse and creative) is also mostly from the Upper Nile as well for the dates of coalsecence of our species (c. 200,000 years ago), although some techno-culture from the Congo basin could also be part of our ancestral presence (but DNA only points to NE Congo at best and there are no skeletal remains, which may be because of jungle environment is horrible for preservation of human remains anyhow).
I estimate that soon after coalescence, maybe c. 170 Ka ago, a branch (mtDNA L0, ancestral to Khoisan people primarily) diverged in East Africa (Tanzania approx.) and would later migrate to Southern Africa. Second to diverge were the ancestors of modern Pygmies, (mtDNA L1), which surely migrated to Central Africa (Gabon, Cameroon, etc., where they slightly admixed with some closely related "archaics", of which we know nothing other than their DNA legacy). Thirdly a major wave surely spread to the Chad area (mtDNA L2, partly precursor of mainline Africans of the Niger-Congo linguistic family), however these retained connection with the Nile region core group because they both ended up with pretty much the same Y-DNA (E and A1(xB,CDEF)).
Finally the Nile core population was finally the source of the "out-of-Africa" migration (c. 125 Ka ago to Arabia-Palestine and North Africa), which carried a few derived lineages: mtDNA M and N, both derived from L3, which has other five sub-haplogroups exclusive of Africa, Y-DNA CF and part of D. These surely reached India c. 90-100 Ka BP (still with African technologies of the Aterian and Nubian types) and soon afterwards SE Asia as well, remaining in those areas until maybe c. 70-60 Ka BP, when they expanded further (mostly from SE Asia although some Indian genetics were also co-opted on the way to West Eurasia, where the "great Neanderthal war" took place (for tens of thousands of years, it's a way of speaking).
Are you suggesting that all humans are African apes?
Thanks
I was always into prehistoric life as a kid but I don’t know much about evolution can anyone recommend me a good book that isn’t outdated.
Quality.
I watched the full video.
Great research, congratulations! It kept me very entertained hehe
Pity no mention of , or explanation of , natural selection! I feel many viewers think we got the hair when and how we needed it rather than the random mutations that gave us these features were favourable to our survival in the environment we found ourselves in and so we survived unlike many other mutations that were not helpful to other life forms and they didn’t.
So, does this mean that straight hair has evoveld as humans strated to live in colder environments where there is less need to block solar radiation?
What about Indians who have very straight hair? India is hot 🔥 🥵
@@fullup91 Good point! It might be about their genetic ancestry. I don't know though.
Indians already likely had straight hair . There is no proof of people having straight hair but went curly like in Africa.
I have a lot more questions. It seems with exceptions that people once they left africa have more or less straight hair. Even in the tropics. The native peoples of Australia and people in southern india do not have kinky hair. But the people on New Guinea that is nearby to Australia have kinky hair? Scattered throughout many of Islands of the indian Ocean are the so called negrito peoples with those of the Anderman Islands really looking much like sub-Saharan africans.
Is there some selective pressure for non-kinky hair?
Even without the experiments, we know that kinky hair is a better insulator. Then we have baldness of various forms. But a simple solution for all of this temperature regulation problem with the cranial contents and sunlight is to wear a hat. That is precisely what desert dwellers do in many regions.
PS baboons and some other monkey groups spend a lot of time in the Savanna with a lot of sun exposure and have straight hair, but again their brains are smaller and perhaps the nasal regions of baboon's expanded muzzle help cool the brain as they do in some non-primate ungulates via heat exchange.