Rat and Exapno, I would really like to understand both sides of your argument a little better but it got beyond me fast. Can either or both of you take some time to summarize for the interested layman?
Here is a fairly good review by Iain Mathieson of harvard.
http://mathii.github.io/review/2015/06/14/lactase-persistence-and-ancient-dna
Anyway too much drift here, just saying that light skin and milk tolerance were two separate events, and while selection may have lead to their spread it wasn’t needed for humans to move farther north. It was just an advantage in competing in an already agriculture based peopled land.
Here is my attempt at simple. it is highly likely that when the pyramids in Egypt were being built, most European adults could not drink milk. It is almost certain that when the Sumerians were inventing cuneiform script almost all European adults could not drink milk.
About 2000 years or so earlier from those Sumerians, or the distance of us from the time of the story of Jesus, most individuals in Europe with blue eyes would have had very dark skin.
In summary; latitude alone didn’t drive the evolution of Europeans’ light skin and ranching/farming alone didn’t drive the evolution of European’s tolerance of milk. Those two traits were also not spread at the same time.
Even that map isn’t quite right, given more recent work. It misses a locus of high LP occurrencein the South West, where Khoe-Kwadi-speaking pastoralists withEast African roots settled.
I’m still confused.
The only cite in that paper of LP was
That’s far earlier than 2007. If age is a factor why cite that?
The abstract merely says that evidence for LP alleles does’t show up in the Bronze Age. That’s a so what. The Bronze Age ended 3300 BC. I made no claim about Bronze Age northern Europeans.
If they are, then give me cites that say that,preferably cites of full articles. Please remember that I am trying to catch up after thankfully not having to deal with genetics for a decade. I just need cites that match your claims.
Because that was a cited source from your cite, which didn’t match your cites’ conclusion. DNA research has moved massively over the past decade which is the reason older studies tend to be more biased to older theories but one must still look at the sources for review.
Yes, it is painful as open access isn’t very well adopted in this field.
Here is one paper that will show why LP has been moved back to the “we dont’ really know why” point.
https://www.ucl.ac.uk/mace-lab/publications/articles/2013/GerbaultPG_et_al_2013IUBMB
Note how they note that rickets isn’t found in earlier populations and while the calcium absorption hypothesis may be found true, the lack of rickets is problematic there.
As they have located cheese-strainers from 7,150 to 6,750 years BP dairying existed in the neolithic, and the areas were peopled. So allele surfing or an advantage for year round food sources in milked animals are also highly likely.
As these areas were peopled by agrarian societies, LP was not a reason that it was beneficial to migrate to these areas as posed in the OP, but rather probably developed as an advantage to groups already in those areas.
As I can’t find a paywall free version, here is a release about this cheese claim, which would have provided the benefits without adult lactose tolerance as cheese doesn’t require LP.
https://www.hw.ac.uk/about/news/2018/researchers-uncover-earliest-known.htm
As that cite only really covered the oldest example of cheese making here is a general overview showing how widespread it was and that the dual meat milk model predated LP by a very long time.
That looks like a good one. I’ll have to study it. Thanks.
Yeah, I think that is it. I’m tired of putting up with dad’s shit. He and his buddies have all the good land, the best hunting sites, and they make all they rules. I do not like their rules. And mom thinks she’s a fucking queen or something.
There is free land just over those hills. Land a man has never seen. Good hunting and good fortunes, let’s go boys (and girls). It is a basic drive of humans to want more, more for themselves and their group. Manifest Destiny on a global scale.
People even braved the vast seas to settle every viable rock, just to have a place of their own.
Curiosity killed the cat, but made Man who he is.
Repeat as necessary, a few dozen miles at a time, and all the resources are taken.
Keep repeating and in time you will colonize Mars.
I do wonder who, hundreds of thousands of years ago, buried himself in a pile of leaves to stay warm one unseasonably cold night - then remembered how nice the fur from the last hunt felt, and that the fuzzy animals didn’t seem to feel the cold, and decided to try to take one of those skins off the next kill and wear it. Or else they dressed ceremonially for a dance about hunting, and remembered one cold night how warm it was in one of those.
Once you get out of central Africa it can get cold enough on occasion to appreciate a removable covering. (Jerusalem got almost a foot of snow a few years ago, and we’re at the peak warmth of the ice age cycle) From there, it’s just a matter of degrees (sorry). If you know how to protect yourself from cold, you can move to slightly colder areas prepared for the occasional weather extreme. And as others also point out, when this migration happens a mile at a time, a dozen miles per generation, it eventually morphs from loincloths and cloaks to boots and full Eskimo parkas over 100,000 years.
The key breakthrough was the initial concept of clothes. Presumably building shelters followed in the same vein - keep the fire warmth in as much as keep the critters from nosing around.
Competition for ‘lebensraum’ is always insufficient as an evolutionary explanation. Simply because there is always competition. If competition caused our ancestors to move to colder climates, then they would have done so already 2, 3, 5, or 20 million years before - because in these times, there was competition for lebensraum, too.
Before 1 million years ago, some individual ancient humans likely tried living in other areas and climates - and died trying. But more recently human ancestors were successful outside east Africa. So something must have changed then.
Competition was not the factor that changed - because competition is always there.
And it can’t just be that circumstances in East Africa changed unfavorably - if that happened, humans would just have gone extinct.
What might have changed is the circumstances in those colder climates. For example, ice ages made large herd animals thrive, and humans successfully hunted them.
Another thing that might have changed, is that humans evolved in response to environmental changes in their East African habitat, and that these new evolutionary changes were by happenstance also useful in colder climates.
For example, evolution resulting in better brains for co-operation and tool-making, would be useful in colder climates too. Of course, it is still a mystery what could have triggered such an evolutionary change. It can not simply be that better brains are always useful - if that was the case, better brains would have evolved long before, and by other animals too.
Modern humans were living at the far southern tip of Africa, so they didn’t need to leave Africa to find relatively cool areas. And, of course, early Homo populations were living in Georgia (in the Caucus region) almost 2M years ago. Our genus has had a long history of exposure to cold dating back much further than the exodus of Sapiens from Africa.
During he African Humid Period between 14,800 and 5,500 BP the Sahara was steppe and forest-steppe while the Sahel to the south was a more arid savanna. As the glaciers receded from Europe tundra gave way to steppe biomes which are similar to areas in Africa where we lived.
Human intelligence hasn’t changed much from 80,000–100,000 BP. The human brain requires more than twice as many calories as the chimpanzee brain and 300-600% more than squirrels, mice, and rabbits. But that evolution pre-dates any movement outside of Africa.
As we were hunter-gatherers and we have examples of fishing like the Antrea Net from around 9300 BP in Finland it shows that following rainfall and steppe is quite possible and nomadic groups dont’ really have the same need for lebensraum which is really based on the discredited ideas of eugenics anyway.
Simple changes in the climate would have lead people to follow the relatively rich food supplies from the marshlands and floodplains of the expanding forest-steppe and steppe.
Here is a recent cite in support of my above post. Note that the transition from HG to farmers was more gradual in the north, and how an aquatic diet was mixed in.
https://www.cell.com/current-biology/fulltext/S0960-9822(17)30559-6
Note that while large game remains are more likely to be preserved, and at one point were thought to be the main source of calories, the paleo diet is now generally considered to be skewed towards plant based diets. The modern fad diet and commonly taught assumptions about the Paleolithic diets are generally myths.
Human foragers managed with what they could find and wet areas are typically more productive.
I should note that outside of simple allele changes like adult lactose tolerance human’s haven’t changed much for 200,000 years.
200K BP is the general date for the arrival of anatomically modern humans, but there is no evidence that modern humans are cognitive superior to Neanderthals.
It is far more likely that changes in climate and bands of suitable habitat enabled these migrations.
As Neandertals arrived at least 350,000 BP and were in Eurasia for over 300,000 years most of our intelligence probably evolved at some point in the history of our common ancestors. The Denisovans were also in Eurasia before modern humans which also suggests that changes in cognitive ability were not a main driver here.
The problem is how humans lived. To live in an area that regularly gets cold - we’re not talking ice age, but even say some climate like Washington or northern Italy today, or even milder than that, where frost and snow is a real possibility -
Then homo had to have the technology of clothes and shelter and fire. Once they figured out those technologies, it was only a matter of degrees.
Another point - humans evolved - and lost their hair - by becoming the best long distance runners on the plains of mid-Africa. Bipedal locomotion and a marvelous ability to sweat out the heat while running gave them remarkable endurance, but a serious vulnerability to cold climates.
Also, they started hunting by running down large animals that could not escape except by running, and eventually lost the race from exhaustion. For humans to feed themselves in other areas, they needed the tools to take down other more elusive game - fishhooks, spears tipped with extremely sharp stone points, clubs and axes with weighted heads tied to long handles, eventually arrows. (And of course, the smarts for planning and driving game into traps)
Once they had the tech - tipped weapons, clothing, shelter, and fire - they were equipped to move on up to the (middle) east side. And… that seems to be what they did. Earlier versions of Homo did in fact move up into Asia, eventually displaced by newer and smarter versions with improved tech.
So, for the OP - were there benefits? Of course, developing tech is always a benefit. the same tech that allowed them to move out to the colder areas also benefitted life in their existing areas.
It’s good that you mention this. The northern third of Africa is arid now but was temporarily much wetter in earlier geological time. The arid and wet periods have alternated over the millennia. When it’s wet in the Sahara and lots of plants and animals flourish, human populations increase there. When the Sahara dries out, there are lots of people moving out to find better living conditions. First it gathers people, then it pushes them out, in a cyclical pattern. It’s called the Saharan Pump, and it has a lot to do with the answer to the OP.
The Earliest tech would I think be knives. IIRC there are plenty of areas where ancient subspeicies of humans first roamed, where you can find the remains of making edged tools from flint. After all, once you’ve chased down a big wildebeest or gazelle and poked it to death with a spear, how do you get at the meat inside? Then the same tool also works to cut new pointy sticks and posts for shelters instead of looking for dead ones that have fallen off.
Homo erectus was the one that moved out of Africa and also mastered fire which would have been useful in areas with more cold and fewer daylight hours.
Around when did humans start using the fur/skin of other animals? I realize that fur coat may not have preserved well through time.
Both of those things are conjecture. We are not sure what the cause was for our losing our hair, or even if there was just one cause. Modern hunter gatherers do often use cursorial hunting, but that is not proof that cursorial hunting was how we, as a species, got into the hunting business.