Human evolution; early ancestor probable upright posture (Introduction)

by dhw, Sunday, September 22, 2019, 10:41 (1679 days ago) @ David Turell

dhw:: Interesting that this is a European fossil. Since there are different types of hominin and homo, one might conclude that different apes evolved differently in different parts of the world. One would expect transitional species to have moved among branches as well as on the ground, and (re your second bold) why should we presume that Rudapithecus did not descend from an all-fours ape? Somewhere along the line, some apes descended from the trees and took to bipedalism. We do not have, and are unlikely to find, a complete set of fossils for every single stage of descent!

DAVID: You are correct. Fossils are few. However on page 258 of my book, Atheist Delusion is Dr. Fuller's exposition of a transitional vertebrae of a hominid form from 21 million years ago in a monkey fossil. Again well before descending the trees.

How do you know it was “well before descending the trees”? Even monkeys descend from the trees! We have absolutely no way of knowing how long all these different apes and hominids spent up the trees and down on the ground!

DAVID: So i repeat my comment:
DAVID: The path to bipedalism obviously started well before the brain enlarged but allowed the hands to become more developed ahead of time, anticipating the further development of the brain's enlargement and capacity for mental development. It didn't require movement to the Savannah to develop as previously proposed, noting my bolds above. I view this as God engineering evolution in a logical fashion ten million years ago.

dhw: Maybe there was more than one path to bipedalism, but I would agree with the whole of your first sentence except for the cryptic "ahead of time", for which I would substitute "when needed": it is logical that the move to a new environment engendered bipedalism, giving rise to new requirements, and so the rest followed on logically

DAVID: Again, the early evidence in time, although scattered, supports my approach not yours; I see preparatory changes, as the authors do, well ahead of the time to descend from the trees. You are still Darwinian in trying to find needs to drive evolution, while as Gould showed, all species arrive fully changed.

Yes indeed, I find it perfectly logical that organisms would change in response to need or to opportunity. Our classic example has always been the whale, and I find your theory that your God changed legs to flippers before the pre-whale entered the water almost laughable beside the theory that legs changed to flippers as a RESULT of the pre-whale entering the water (for whatever reason). The same applies to our various ancestors. I envisage them spending increasing amounts of time on the ground (for whatever reason), and their bodies adapting to cope with the different conditions. What do you mean by “fully changed”? All species (in the narrow sense of variations) are fully changed in the sense that they are individual, functioning life forms. You have referred us to p. 258 of your excellent The Atheist Delusion and to Dr Filler’s findings. I quote:

p. 258: “He demonstrates changes in lateral processes that begin to allow for the development of completely upright posture over the the course of the next 20 million years of evolution.”

It took 20 million years for the “complete change” we are discussing! And it took umpteen different “species” of hominid and homo to get there! And so apparently your always-in-control God, whose one purpose was to specially design H. sapiens, either preprogrammed all these different changes 3.8 billion years ago, or kept fiddling and twiddling with hominid/homo anatomies for 20 million years in anticipation of each change in their environment! No wonder you have no idea why he would have chosen this method of “evolving” (= special designing) the only thing he wanted to evolve.

xxxxxx

Under “Evolution and humans: big brain birth canal”:

QUOTE: Preliminary work on the pelvis of the recently discovered 1.98 million-year-old hominin Australopithecus sediba found it to possess a unique combination of Homo and Australopithecus-like features.

All complete in themselves, but suggestive of convergent evolution as each “species” works out its own evolutionary course.