Human evolution: savannah theory fading (Introduction)

by David Turell , Monday, March 03, 2025, 17:34 (3 days ago) @ dhw

DAVID: The 300,000 years ago proviso tells us this discussion is about sapiens. But it roughly covers intermating with Neaderthals and Denisovans.

dhw: In that case, it tells us nothing about the origin of sapiens. So how does intermating come to mean the savannah theory is fading? [[…[

DAVID: It is all from single studies of single spots.

QUOTE: “The secure attribution of stone tool assemblages with the wet forest environment demonstrates that Africa’s forests were not a major ecological barrier for H. sapiens as early as around 150 ka.
"Most importantly, however, our results confirm a deep-time connection between human evolution and tropical forest biomes, opening up a new chapter in the human past in which our species occupied dense, wet tropical forests much earlier than widely thought.

DAVID: based on this evidence we weren't forced out into savannahs.

dhw: This evidence tells us that sapiens was already sapiens when he lived in the forests. It tells us nothing about how sapiens first became sapiens.

DAVID: Does that matter? The argument is did savannahs force sapiens evolution? What I presented says 'no'.

dhw: What you presented says no such thing. It only tells us that sapiens lived and mated in forests as well as elsewhere, and did so earlier than we thought. But perhaps you have left out a passage which rejects the savannah theory?

DAVID: This quote might help you:

"The new findings also strengthen an argument that H. sapiens evolved roughly 300,000 years ago via mating among populations based in different African regions and habitats, including West Africa’s rainforests. Even around 150,000 years ago, “when these groups coalesced, their exchanges shaped the course of our evolution and likely contributed to the success of our species,” Scerri says."

dhw: So who mated with whom to produce the brand new species? This quote suggests that 300,000 years ago, different non-sapiens mated in different regions and habitats, and all of these different non-sapiens produced the same sapiens, who 150,000 years ago mated with various non-sapiens, thus contributing to the success of sapiens. Does that make sense to you?

Sapiens appeared 300,000 years ago, just as Neanderthals did ~600,000 years ago. All new forms simply appear. The interspecies mating helped make the sapiens we know. I don't understand your problem.