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

by dhw, Thursday, March 20, 2025, 09:19 (14 days ago) @ David Turell

dhw: At least you now agree once more that complexity and enlargement occur IN RESPONSE to environmental changes, and not in anticipation. How does one “guide” enlargement and complexification? Did your God pop round to each pre-sapiens in the group with his X-Ray machine and scalpel, making sure the cells were arranging themselves in the right order?
As usual, you have ignored my question.

DAVID:I have no idea how God enlarges brains or increases the complexity. But each increase provides for the present and future needs.

How else could he do it without some kind of individual operation? Don’t you think it would be less of a chore for him if he just created a mechanism that would perform the same functions? Your second sentence fits in perfectly with the history I have presented: each enlargement is a response to new requirements that exceed the present capacity for complexification; the same size is maintained till the next requirement that exceeds the capacity, and so on until we reach sapiens, and as further expansion is not possible, it is enhanced complexification that copes with all future requirements. You’ve got it!

DAVID: The Erectus brain covered many complex problems, but could not handle today's requirements. Even though ours is 315,000 years old it works just fine. That is anticipation of needs.

In fact, the erectus brain gradually expanded until it came very close to our size. Something triggered the final expansion to our size, and from then on, complexification has coped with all new needs, as it did with every other species until additional cells were required. Each expansion is a response to new needs; the additional cells are not the result of crystal-ball gazing and then hanging around for thousands of years, in our case waiting to invent railways and rockets! They are in constant use, and complexify as and when required to do so. Currently demonstrated by the examples of the illiterate women and taxi-drivers.

The savannah theory

dhw: May I take it that you now agree that the savannah theory concerning the origin of sapiens is as logical as any other theory, including your own, in which your God operated on a group or groups of legs, pelvises and brains?

DAVID: Yes the savannah theory is logical. But the real story is unknown.

Thank you. We are in agreement.

Human evolution: adding to our genome

QUOTE: "The ancestors of all modern humans split off from a mystery population 1.5 million years ago and then reconnected with them 300,000 years ago, a new genetic model suggests. The unknown population contributed 20% of our DNA and may have boosted humans' brain function.

DAVID: sort of clarifies dhw's question about our origin.

Not really. There are no details given. Were they a group of African tree-dwellers who descended to the savannah? Or you yourself might ask if they existed in several groups, to each member of which your God personally gave new legs, a new pelvis and a new brain before they descended.