Human evolution; savannah theory fading (Introduction)

by David Turell , Friday, August 19, 2022, 18:54 (825 days ago) @ dhw
edited by David Turell, Friday, August 19, 2022, 19:29

Brain expansion

DAVID: Why is one of God's actions feasible (complexification) and brain enlargement not? Sticking to confused attempts at theism!!!

dhw: That is the question I keep asking you! My theistic proposal is that he gave cells the autonomous abilities to complexify and to multiply. You agree to the first, and reject the second! Why?

Same old answer: cell committees are not capable of design for future uses and needs.

Prehistoric brains and pelvises

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

dhw: But do you now accept the possibility that there would have been a lot of deaths in childbirth, as I proposed above?

DAVID: No. But more than ours now, yes.

dhw: So we return to my solution to the “pelvic problem”. It would have taken time for the relevant cell communities to adjust to the new sized baby skull, and no doubt this would have caused a lot of deaths in childbirth. Your objection is no longer that your God stepped in to ensure that there were no messy deaths, but God stepped in to ensure that there were fewer deaths than “a lot” of deaths.

I'm looking at pre-historic birthing in light of the present difficulties. Obstetricians currently can solve more complications than cave folks back then. God did what he could to accommodate walking and big head birthing all at once.

Genetic formation of our pelvis:

https://www.sciencemagazinedigital.org/sciencemagazine/library/item/19_august_2022/4035...

"The wide, basin-shaped human pelvis is a defining physical feature of our species. Without it, we couldn’t walk upright or give birth to big-brained babies. Now, a new study of human embryos has pinpointed the window in embryonic development during which the pelvis begins to look humanlike and identified hundreds of genes and regulatory RNA regions that drive this transformation. Many bear the hallmarks of strong natural selection for bipedalism, the authors conclude.

***

"By comparing the developing pelvis’ genetic activity with a mouse model’s, the researchers also identified thousands of genetic on/off switches seemingly involved in shaping the human pelvis. Stretches of DNA within those switches appear to have evolved rapidly since our species’ split from our common ancestor with chimpanzees. But among modern humans, those regulatory bits in the ilium show strikingly little variation. That uniformity, the researchers say, is a sign that natural selection put—and continues to put—intense pressure on the ilium to develop in a highly specific way."

Comment: all that genetic activity by cell committees? Impossible!!!

Hemispherectomy

DAVID: 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.

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

dhw: That is all they need now, since expansion has ceased and complexification has taken over. But I’m happy with your conclusion, as you agree that brain cells are capable of changing themselves autonomously in order to meet new requirements. If brain cells can do this in the present, and we know for a fact that other cells can also make the minor changes necessary for adaptation, there is no reason to assume that other cell communities did not have the same autonomous capabilities in the past, when full speciation took place (as opposed to varieties, which we also call species). The current period of evolutionary stasis is very short compared to those of the past, and who knows what new species might be formed by the same autonomous mechanisms if (when?) our planet – or parts of it - undergoes radical changes? It is pleasing to see you gradually coming round to the fact that your God could and did give a degree of autonomous, creative intelligence to cell communities.

DAVID: Not evolutionary stasis. We are its endpoint under God's designs.

dhw: I’m pleased to see that you have no objections to my argument that past cells might have had the same autonomous abilities as present cells to make the changes needed to meet new requirements. Whether evolution has now finished is a question none of us can answer – unless you happen to have a reliable crystal ball to observe Planet Earth as it will be in, say, a billion years’ time.

I still reject your cell driven enlargement of the brain. I ignored responding to it above.