Discussion in 'General Science & Technology' started by geek, Dec 6, 2017.
It was more of a drift than an escape.
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If they could exist and survive in Africa from the start with that continent's animal population, then why would the latter be a barrier to their migrating out? Your question of skeptical context seems to take it as a given that humans were in Africa. It is not expressing suspended belief about that, but doubt about their ability to depart due to the wildlife. Which is undermined by the aforementioned unless something more can be provided to justify why the animals would have been an obstacle to travel beyond the continent, since they were not an obstacle to travel within it (as well as people subsisting therein).
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Humans Migrated Out of Africa to Escape Drying Climate, New Study Says
Oct 17, 2017 by News Staff / Source
"Ancient humans left Africa to escape a drying climate, about 60,000 years ago — a finding that contradicts previous suggestions that humans were able to leave because a then-wet climate allowed them to cross the generally arid Horn of Africa and Middle East. The study is published in the journal Geology.
While humans may have left Africa earlier, genetic research indicates that the main out-of-Africa migration probably occurred between 70,000 and 55,000 years ago.
“It has long been proposed that the out-of-Africa migration was facilitated by wet periods that created green corridors to Eurasia — in other words, the climate pulled people out. We may have to revise this model to one where people were pushed out, due to unfavorable conditions,” said study co-author Dr. Peter deMenocal, of Columbia University.
Dr. deMenocal and colleagues traced the Horn of Africa’s climate 200,000 years into the past by analyzing a core of ocean sediment taken in the western end of the Gulf of Aden, off present-day Somalia.
“There’s always been a question about whether climate change had any influence on when our species left Africa. Our data suggest that when most of our species left Africa, it was dry and not wet in northeast Africa,” said lead author Dr. Jessica Tierney, from the University of Arizona.
The researchers analyzed the sediment layers for chemicals called alkenones made by a particular kind of marine algae.
“The algae change the composition of the alkenones depending on the water temperature. The ratio of the different alkenones indicates the sea surface temperature when the algae were alive and also reflects regional temperatures,” Dr. Tierney explained.
To figure out the region’s ancient rainfall patterns from the sediment core, the authors analyzed the ancient leaf wax that had blown into the ocean from terrestrial plants.
Because plants alter the chemical composition of the wax on their leaves depending on how dry or wet the climate is, the leaf wax from the sediment core’s layers provides a record of past fluctuations in rainfall.
The team found that around 70,000 years ago, climate in the Horn of Africa shifted from a wet phase called ‘Green Sahara’ to even drier than the region is now. The region also became colder. "
Even that headline is a bit misleading.
Humans simply husbanded the land. If resources dried up, they would have to move to a new location. Some went west, some went east. It is an emergent property of these small, local movements that, ultimately had them to a gulf, to cross it, and to find new land in Europe.
It is a real privilege to live in this scientific age.
I dont like to have answers from Drying Ie the deserts,the under privileged in flora and fona. Nor do i need answers from snowing, much More under prevelidged. Both the same. so Cut it out.
I need answers from africa, why is it lush fertile and who on earth would ever just walk off her, No one would. No one can. Africa is by so far the Mother of all fertility. The snow guys or the dry Desert guys need to bow on to Africa. Simple, Coz they are under prevelideged in their thoughts, their , Air, Their sands......... their every thing. even their oxygen , even their sunlight.
In absence of essentials, ie air, flora an fona. how can the dry guys, or the snow guys,they ever think any thin straight...... They have the lack of Clean Oxygen.
Uh . . . . have you ever been to Africa?
?? I did. (Well, I flew off her, actually.) I imagine there are a few other people did as well.
Have you been drinking?
And latest thinking is the veldt was drying up, so they had to move to a more verdant climate.
Anyway, the area wasn't wall-to-wall lions, and the humans were exactly harmless themselves.
Sure they would. Why would people just walk up to the arctic? Why would people get in boats to go live in Iceland or Greenland? Why would people living on an island paradise get in little more than large canoes and set out on a 1000 mile journey into the unknown Pacific ocean? Seems like no one, but damn if they didn't!
Seems like you just are way under estimating what people are capable of.
And, once again, the Sahara region was drying out rapidly. We have cave paintings near a dried up lake that show hippos and giraffe cavorting in the waters of that (now former) lake.
Especially if the alternative is living with the inlaws in a hunted-out landscape.
(inlaws, like grandmothers, are characteristically human innovations on this planet)
Jared Diamond, in his book "Collapse", includes interviews and accounts derived from the governing adults of a couple of such island paradises, in which not only their motives but their actual procedures for doing that are made clear.
In one smaller such paradise, for example, the carrying capacity of the island complex had been calculated long ago, and when the population grew beyond it the community had fissioned - those chosen to leave did so, in a fleet of boats over the Pacific, to either found a new colony or die at sea depending on their fortune.
In modern times Mennonite communities do something similar - not into the unknown, in their case.
Doesn't substantiate your original post.
Separate names with a comma.