Human evolution: savannah theory fading; big brain (Introduction)

by dhw, Friday, March 14, 2025, 11:13 (5 hours, 8 minutes ago) @ David Turell

The human brain

dhw: Our big brain, which you now seem to accept as having evolved from earlier brains (as opposed to your God having performed one of his many operations on our sleeping ancestors), has clearly given us advantages in the great dog-eat-dog battle for survival, which you accept as an explanation of evolution’s history.

Ignored by you. I gave you an example of how a new concept (the hunter’s spear) might require new cells for design and implementation.

dhw: The early brain’s capacity for complexification was limited, and so it required new cells – hence expansion. Multiply the scale of this example by the demands made by a new environment. Cause and effect all the way through until the brain (sapiens) could expand no further and complexification took over. Remember?

DAVID: Yes, I remember this non-answer. We see a 300,000 old brain hardly-used to capacity at the time.

dhw: We have discussed this ad nauseam. After much huffing and puffing, you agreed (a) that the brain RESPONDS to new challenges (as opposed to anticipating them) and would always have complexified, or expanded when the capacity for complexification was exceeded, and (b) that ALL of our expanded sapiens brain would have been used from the outset, not hanging around doing nothing for 300,000 years, and further developments were implemented through complexification and not expansion. I don’t know why you’ve raised this subject again, but we can use it as an example of how new conditions (e.g. savannah as opposed to forest) may lead to anatomical changes, including changes to the brain.

DAVID: Our agreements apply to the large existent brain , not how it got to be so big and complex.

Explained above, with the small example of the spear, extending to the huge example of new environmental conditions requiring new responses. All agreed years ago.

dhw: […] our subject here is the origin of sapiens: why is your divine surgery on groups of ancestors more likely in your eyes than a group of ancestors being forced from the trees, surviving in the savannah, and spreading far and wide into all sorts of environments?

DAVID: The new findings timing in history negate the savannah theory. There were lots of non-savannah folks living all at the same time.

dhw: The new findings show that they were living with sapiens. They could not have been living with sapiens if sapiens did not exist. And the question answered by the savannah theory is HOW sapiens came to exist – not what he did after he had come into existence.

DAVID: The savannah theory was a phantasy based on one finding.

It is a logical explanation for bipedalism and brain expansion. Please tell us what findings confirm your theory that there is a God who performed operations on the legs, pelvises and brains of one group or multiple groups of our ancestors.

dhw: Nothing is certain. Even you can’t explain why your God would go on designing life form after life form for 3.X billion years before designing “de novo” the only forms he wanted to design. Nor does it make sense that your all-powerful God should have “evolved” all kinds of hominins and homos, but then had to perform operations on particular groups to turn them into the only species he really wanted - sapiens with new legs, pelvises and brains.

DAVID: What is simple is we do not understand the use of evolution by God.

Even if we accept the existence of God, there is no logic that can possibly justify your theory that his sole purpose for creating life was to design us and our food and so he had to design and cull 99 out of 100 species that had no connection with us and our food. Please stop pretending that your illogical theory is the only possible explanation for evolution.

Earliest humans in Europe
At 1.2 million years ago:
https://www.sciencenews.org/article/western-europe-face-fossil-evolution

QUOTES: "Excavations at a site known as Sima del Elefante produced several fossil fragments that, when pieced together, form a partial left upper jaw and cheek bone dated to between 1.4 million and 1.1 million years old…”
"Fossil remains of four H. erectus faces at Dmanisi display considerable variation in nasal structure and other midface traits, Rightmire says. One of those faces aligns closely with the Spanish midface discovery, he contends. After H. erectus left Africa, “I would put my money on a long-lasting regional [H. erectus] population occupying Dmanisi around 1.8 million years ago, with later populations moving into Europe,” Rightmire says."

DAVID: this puts us out of Africa at a very early time compared to other evidence.

The movement to different environments would certainly explain different traits between members of our own species. But of course it doesn’t tell us anything about the origin of our species.