My assumption: like with any territorial animal, to avoid competing with other tribes over resources. And apart from the very very cold places like Greenland, most cold places actually are abundant in food when spring comes, which would be the time tribes would venture further north in cold climates.
And it’s not like someone went from Africa to Greenland on a walkabout.
It took generations for that kind of migration, some people decided they went far enough and stopped. But at every stop, the ones who could handle colder would expand North/South where there’s less competition.
They were repeatedly being selected for the people who could handle a slightly colder environment, so by the time the population reached the polar regions, all that was left was people with traits to handle the cold. Any remotely beneficial recessive gene would quickly replace dominant alleles in the population.
People think of evolution as spontaneous mutations, but really it’s just the concentration of recessive genes that have been around basically forever
My assumption: like with any territorial animal, to avoid competing with other tribes over resources. And apart from the very very cold places like Greenland, most cold places actually are abundant in food when spring comes, which would be the time tribes would venture further north in cold climates.
Yep.
And it’s not like someone went from Africa to Greenland on a walkabout.
It took generations for that kind of migration, some people decided they went far enough and stopped. But at every stop, the ones who could handle colder would expand North/South where there’s less competition.
They were repeatedly being selected for the people who could handle a slightly colder environment, so by the time the population reached the polar regions, all that was left was people with traits to handle the cold. Any remotely beneficial recessive gene would quickly replace dominant alleles in the population.
People think of evolution as spontaneous mutations, but really it’s just the concentration of recessive genes that have been around basically forever