Human evolution; savannah theory fading (Introduction)

by David Turell , Wednesday, August 17, 2022, 19:01 (827 days ago) @ dhw

Brain expansion

dhw: [...] how do you know his exact wishes, and how does this prove that he did NOT give cells the ability to multiplY?

DAVID: Cells do multiply. Why did you ask? And I have said we cannot know God's personal reasons.

dhw: You keep telling us that early brain cells could not have added to their number, and so God had to engineer their expansion (multiplication). Do you now accept that early brains might have had an autonomous mechanism for expansion as well as for complexification?

DAVID: Our brain's abilities reflect the past brains. I assume they worked as ours does, new neurons in hippocampus only.

dhw: I agree totally that our abilities reflect those of the past, i.e. that the cells could autonomously complexify (you agree) and multiply (as shown by the modern hippocampus), and we have agreed that otherwise, complexification took over from multiplication in the sapiens brain. You have no reason to assume that your God did not give both abilities to the brains of our predecessors.

You can assume that possibility as pure unsubstantiated theory.

Prehistoric brains and pelvises

DAVID: It turns out our birth canal is still tough to navigate.

dhw: Yes indeed, so why do you think our pre-historic ancestors had no trouble back in the days when baby skulls got bigger?

DAVID: I'm sure they faced the same obstetric problems we do.

dhw: Probably a darn sight worse. So what is all this about God arranging it “so new heads fit into new sized brains all at once”? [dhw: see below for the complete quote.]

DAVID: Old homo birth canals were just like ours under God's designs.

dhw: My answer to what you called the “pelvic problem” was that the cell communities would have adjusted themselves to accommodate the new sized skull, but no doubt there would initially have been a lot of deaths during childbirth. You pooh-poohed this possibility because God would have arranged it “so new heads fit into new sized brains all at once without all those messy deaths you prescribe”? Do you now accept the possibility that there would have been a lot of deaths during childbirth as a result of the new sized skull?

My kind God provides for all required changes as He designs for future use.

Hemispherectomy

QUOTES: "Adults who had one half of their brain removed in childhood to treat seizures can still recognise faces and words at a reasonably high level, suggesting that the organ can reorganise itself after major childhood surgery.”
“The fact that above-chance and broadly comparable performance for face and word recognition can be achieved following childhood hemispherectomy attests to the remarkable adaptability of the juvenile brain,” says David Wilkinson at the University of Kent in the UK."

DAVID: Makes the point!!!

dhw: It certainly does. You could hardly have a clearer illustration of the way brain cells autonomously change themselves in order to meet new requirements. Or do you think your God pops in to perform additional operations after the surgeons have done their job?

DAVID: No, He gave the brain the abilities we see. No stepping in.

dhw: Thank you for confirming my proposal that if God exists, he would have given cells the autonomous ability to change themselves in order to meet new requirements.

All He gave the neurons is the ability to arrange new networks of connections in complexification.