Human evolution; savannah theory fading (Introduction)

by David Turell , Wednesday, July 13, 2022, 18:02 (652 days ago) @ dhw

DAVID: The erectus brain developed in Africa and the erectus wandered all over the Earth handling new environments with ease. You can talk all around that without changing the import of that history. The brain came before all the required uses in subsequent migrations.

dhw: Why have you suddenly skipped millions of years and hominins and homos? The subject is human evolution. Our history reaches back millions of years to small-brained hominins who apparently still lived in forests, although it is possible that their environment was mixed. Lucy’s brain capacity was about 400 cc. What you call the “new big brain” was the result of expansion over millions of years as hominins and homos encountered new conditions and environments. We know the brain RESPONDS to new requirements. When you say: “The brain came before all the required uses”, yes, the little brain was there from the start, and it gradually became bigger as it learned to cope with or exploit new conditions, but Lucy was not born with the “new big brain”! Even erectus wasn’t born with the “new big brain”, since his/her brain appears to have expanded from approx. 850 cc to 1000 + cc. I’d hoped to avoid a repetition of our discussion on brain expansion, but you still seem to be hooked on the notion that every expansion was a divine dabble IN ANTICIPATION of new requirements.

I agree the Erectus brain increased over time, but a key thrust of the article is Erectus
migration from Africa all over the world, as I stated above and from the article:

"The Pleistocene, which began about 2.58 million years ago and ended around 12,000 years ago, saw hominin horizons extend beyond Africa. From 1.8 million years ago, stone tools turn up in the cool climes of Dmanisi in Georgia and later in wet and windy Norfolk in the United Kingdom. Finds of crafted ‘Acheulean’ hand-axes act as ‘breadcrumbs’ for the extension of our genus from Africa into South Asia, the Middle East and Europe between 1.7 and 1 million years ago. Homo erectus was a key hominin player in this expansion. This hominin emerged in Africa around 2 million years ago and, as the name suggests, specialised in walking upright. Discoveries of stone tools and butchered animal carcasses suggest it also focused on hunting and scavenging meat from animals, including elephants and antelope, and preferred open grassland environments.

"With this meaty menu in mind, the first expansions of our ancestors beyond Africa have often been associated with periods of climate change that would have resulted in the extension of grassland ‘corridors’ out of Africa. Extending across the Middle East, Europe and Asia, these habitats supposedly provided open conveyor belts for the large animals that had become important sources of food for hominins. According to this theory, our ancestors followed their prey out of the continent. But what happened when these early hominin navigators reached tropical forest realms beyond Africa? We know that Homo erectus had made it to Java in Indonesia 1.5 million years ago. Was it met by a wall of dense tropical rainforest, or did it benefit from the penetration of grassland corridors down towards the equator?"

The brain came first and the migration afterward and did enlarge within the same species as new experiences occurred. Note! In contrast to our brain shrinking with new complex advanced uses. Why? I view us as a completed endpoint while Erectus was a work in progress as God designed it.