quote:
The idea that humans originated in sub-saharan africa and spread from there never made much sense to me. The sahara desert is nearly the size of the united states. No primitive people were crossing that desert to populate other lands. They would have been cooked and died.

1. the article is about beings that lived 7 million years ago.
nothing you would call human lived until a few hundred thousand years ago, probaby not even that. Neanderthals and the Denisovans were afoot.
if you look at the research closely, you do not see what you would call humans, several hundred thousand years ago. 1/3rd sized brains, for instance.
there were MANY hominids.
2. as for your climate issue, climate changed many times over the millions of years, as cycles like the movement of the Milky way, and within our galaxy changed too. Sun around the galaxy every 26,000, right?
the saraha probably did not appear until recently.

This post was edited on 5/23/17 at 6:31 pm

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Posted by DawgfaninCa

San Francisco, California

Member since Sep 2012

20092 posts

Posted on 5/23/17 at 6:50 pm to CelticDog

quote:
the saraha probably did not appear until recently.

Not according to most scientists.

quote:
Before the great desert was born, North Africa had a moister, semiarid climate. A few lines of evidence, including ancient dune deposits found in Chad, had hinted that the arid Sahara may have existed at least 7 million years ago. But without a mechanism to explain how it emerged, few scientists thought that the desert we see today could really be that old. Instead, most scientists argue that the Sahara took shape just 2 to 3 million years ago. Terrestrial and marine evidence suggest that North Africa underwent a period of drying at that time, when the Northern Hemisphere started its most recent cycle of glaciation.

LINK

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