That's not strictly true. If we assume that a person provides little/no value to the group until the age of 10-11. Then someone who lives to 50 as opposed to 40 spends 10 more years working productively for the betterment of the group. This of course assumes that they produce more benefit than detriment to the group during those 10 years.
Thus if there are group selective pressures at play. Those with adults who live longer may outcompete those who do not.
And it may explain why darker skin (which has less incidents of skin cancer) was selected for at lower latitudes, while white skin (more effective as absorbing vitamin D) was selected for at higher latitudes.
The paper doesn’t specify why these genes might have been under such strong selection. But the likely explanation for the pigmentation genes is to maximize vitamin D synthesis, said paleoanthropologist Nina Jablonski of Pennsylvania State University (Penn State), University Park, as she looked at the poster’s results at the meeting. People living in northern latitudes often don’t get enough UV to synthesize vitamin D in their skin so natural selection has favored two genetic solutions to that problem—evolving pale skin that absorbs UV more efficiently or favoring lactose tolerance to be able to digest the sugars and vitamin D naturally found in milk.
Life expectancies were longer than people think back then. A lot of times we see stats that are dominated by high infant mortality. If you lived to 10 you were gonna make it a while.
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Not to mention that it’s not hard to suppose that they lived to be old enough to reproduce before they all died from skin cancer...
That's a really good point.
No evolutionary pressure once someone has reproduced, and skin cancer and skin cancer is both rare under 30[1] and take some years to kill.
[1] https://www.cancerresearchuk.org/health-professional/cancer-...
Offspring with living parents and grandparents have incredibly better odds at surviving.
That's not strictly true. If we assume that a person provides little/no value to the group until the age of 10-11. Then someone who lives to 50 as opposed to 40 spends 10 more years working productively for the betterment of the group. This of course assumes that they produce more benefit than detriment to the group during those 10 years.
Thus if there are group selective pressures at play. Those with adults who live longer may outcompete those who do not.
Fair point.
And it may explain why darker skin (which has less incidents of skin cancer) was selected for at lower latitudes, while white skin (more effective as absorbing vitamin D) was selected for at higher latitudes.
The paper doesn’t specify why these genes might have been under such strong selection. But the likely explanation for the pigmentation genes is to maximize vitamin D synthesis, said paleoanthropologist Nina Jablonski of Pennsylvania State University (Penn State), University Park, as she looked at the poster’s results at the meeting. People living in northern latitudes often don’t get enough UV to synthesize vitamin D in their skin so natural selection has favored two genetic solutions to that problem—evolving pale skin that absorbs UV more efficiently or favoring lactose tolerance to be able to digest the sugars and vitamin D naturally found in milk.
https://www.sciencemag.org/news/2015/04/how-europeans-evolve...
Simpler than that: just being sunburnt is a disadvantage, no need to get cancer.
Life expectancies were longer than people think back then. A lot of times we see stats that are dominated by high infant mortality. If you lived to 10 you were gonna make it a while.
That's also not necessarily true either. Even accounting for infant mortality, people died much younger than we do today.
Sure, people did occasionally live to old ages, but only the ones who lived easier lives.
Today, the top 5 places where people live the longest are three islands, one peninsula, and a place filled with vegetarians who don't smoke and don't drink alcohol. https://www.aplaceformom.com/blog/2013-03-29-where-people-li...