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
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.
Although I’m sure there was some genetic adaptation, I’d argue it was more technological advancement. The northernmost tribe discovers a better make of clothing, or a better housing structure and suddenly the colder winters farther north are now tolerable so people settle there. The new northern tribe refines their technology and knowledge and now that they know how to… ice fish or something they have a winter food source, and now their descendants can settle even farther north.
Although I’m sure there was some genetic adaptation
It wasn’t so much spontaneous adaption…
There’s more genetic diversity inside of Africa than outside of it combined.
Very very few mutations have occured outside of Africa. Blue eyes is one of the few examples, but that was a perfect storm of something just breaking (what made pigment in the eye), allowing for greater nonverbal communication (pupil dilation became more obvious), and being very very obvious no matter how much clothes you were bundled up with.
It’s just Africa is so fucking diverse, that it’s rare for populations to become truly isolated and for the same certain recessive genes to become the most popular variation within a fixed population. It’s mostly just things like sickle cell that provides a benefit against a common cause of death even when recessive and only one copy is present. It’s been a minute, but I think when one copy is the most beneficial is the fastest way to get rid of the dominant for some reason I can’t recall.
So I wasn’t talking about tribes mutating on the march North.
I meant the people who would expand north were more likely to have the recessive traits, mate with others, and consolidate them.
Besides, neanderthals had better tech then we did. The advantage was our faster reproduction cycle which allowed not just for greater numbers, but faster concentration of beneficial recessive traits to suit changing environments.
So like…
We have a real example that tech was second place to biology. This ain’t a hypothetical. You’re right tech played a part, just a smaller part.
My guess would be that it happened gradually. Someone living in a place where the minimum temperature is 15 might be willing to move north to a place where the minimum temperature is 13 as long as other factors are better for him. Couple of generations later you have someone who’s living in a place where the minimum temperature is 13 willing to go north to a place where the minimum temperature is 10, so on and so forth.
It happened even more gradually.
Your kids moved out of the house when they were adults and built their own, a mile over the next hill north, cause the other good spots were taken. Repeat x 10000 and you’ve “migrated” all over the globe.
The current era of excess is unprecedented in the history of the world. For most of human history, starvation was a serious threat and hungry people would go anywhere where there was food that wasn’t already claimed by someone stronger than them.
(The people in very cold climates would fight to defend their resources too! Ultimately there was no unclaimed land that people could survive in, except shortly after major catastrophes.)
As a Finn, I’ve often wondered about the same thing. In the summer the air is filled with mosquitos and in the winter it hurts your face and lungs yet some people were like “yep, we’ll settle here”
Maybe all the people south at the time were assholes with pointy sticks.
Indeed, they’re now called Slavs and Germanics.
Because they weren’t necessarily always harsh, cold environments. The global temperature has fluctuated significantly in the last 1000 years or so. We had a medieval warming period from about 1000AD through 1200AD, followed a couple hundred years later by a “little ice age”. Technically, our world is still in an ice agethough the last 12,000 years or so have been remarkably stable compared to the longer scale geological timeframes ice ages generally span. Good thing our dependence on fossil fuels has upended our real handy metric for tracking this kind of stuff so we now have basically no clue wtf is going to happen climate wise in the next 10,000-12,000 years. Warhammer 40k is very optimistic about humanity lasting that long.
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Competing with ice and snow can be far less stressful, dangerous, and depressing than competing with other humans and tons of other species.
We basically spread to everywhere that could support us. If there was food, people lived there.
Not only cold. Without AC the south of USA would be completely different too.
There have been some good responses…
I’ll add my poor one.
Adventurous people, wanting to be away from others would also weigh in.
As above no one moved to Norway from the Fertile Crescent.
People had to figure out clothing and fishing and hunting and farming then how all those things we different as they move further north. James Burke, in Connections points out how the plow changed. In light sandy soils a stick works, but in heavy wet clay you need heavy curved iron plows.
So. Why? Because Bob smells, and never cleans up. We’re outta here — but over 10000 years give or take.
I think you’re on to something; I’m an introvert norwegian, and I’m a social recluse even by norwegian standards. I’ll take sideways sleet any day rather than risk being spoken at.
Get away from assholes ?
Hunting seals and whales in some cases, as in Alaska.
Yep, following food.
Or, it wasn’t as harsh when they first appeared. I mean there was the Little Ice Age in Shakespeare’s time, where the Thames froze over. If you took that as a sign it was becoming permanently like that in London, what would you do? It’s not like you have somewhere else to go that you know it’s better (or hell, where anything is).
People in the 20th century easily forget how little knowledge the average person had even 100 years ago. Hell, even the information the wealthy had. Just a couple hundred years ago a globe of the earth was practically priceless. They were still a luxury in the early 20th century.
It’s a good point that competition can drive animals to areas they wouldn’t choose. But it’s also true that pioneering a new niche can lead to animals thriving rather than just surviving.
Many of the northern settlements were escaping war, pillaging, and plundering.
Also the climate may have been a bit less harsh one thousand years ago
My understanding is that we are currently living in an interglacial period.
I believe the pattern on Earth recently has been you get these relatively mild climates that last around 10 thousand years, in between 100 thousand years of ice age.
So, maybe the climate was harsh pretty much everywhere that wasn’t the equator for most of time our species has existed.
