Evolution and humans: all over Africa; addendum (Evolution)

by David Turell , Sunday, May 06, 2018, 20:53 (2391 days ago) @ David Turell

dhw: I’m glad you’ve dropped the starting point argument. I’m sorry you have not been able to tell us of any current studies that support your hypothesis that the brain changes before it has the concepts that require it to change. I have offered my explanation for the pfc expansion. Your God could speciate by designing a brain that thinks for itself and is plastic enough to engineer its own changes.

David: Your request for studies into enlargement of the brain have no basis of facts in which to work. All we've got is fossils to measure. As for what God did, I feel He was/is in charge of what evolution did/does. His work is the best explanation for the arrival of eh human brain. Your theory simply accepts that.

I've found a theoretical study about how human brain growth starts:

https://www.sciencedaily.com/releases/2018/05/180504103802.htm

"The superior size and complexity of the human brain compared to other mammals may actually originate from fewer initial starting materials, new research has suggested.

"A team from the University of Oxford and Cardiff University have used mathematical models to re-enact the complex process of brain development that occurs as initialising cells, otherwise known as progenitor cells, start to grow and begin to differentiate into more specialist cells at various points in time.

"By applying this experimentally realistic model to mice, monkeys and humans, all of which use roughly the same type of raw materials to develop a brain, the team identified the different brain development strategies that separates each of the three mammals.

"In particular, the equations looked at the ability of progenitor cells to divide either into more progenitor cells or into neurons. The equations were then linked to real-life experimental data from mice, monkeys and humans and used to predict the original population of progenitor cells before the brains started to develop.

"The results showed that the human brain may develop from fewer raw materials compared to both mice and monkeys, which is surprising given that a human brain is much more complex than that of a mouse.

"Indeed, the cerebral cortex in the human brain, which is accountable for high cognitive functions such as language, memory and movement, contains approximately 16 billion neurons -- the cerebral cortex of a mouse contains around 14 million neurons. (my bold)

"Similarly, the brain of a mouse weighs around 400 mg whereas a human brain weighs roughly 1,500,000 mg.

"Interestingly when comparing the brain of a monkey to a mouse, the results showed that the monkey brain is developed from more initial cells, leading to the creation of a larger brain.

"The team have proposed that as the human brain has been formed and sculpted through more than 500 million years of evolution, it has been able to develop more strategic ways of creating complex structures with fewer cells.

***

"Dr Noemi Picco, from the University of Oxford, said: "To produce a larger brain we can either stretch development over a longer period of time or adopt an altogether different developmental program to produce neurons more efficiently within the time available.

"'It seems plausible that humans adopted the first solution as our gestational period is much longer than a mouse's, rather than starting off with more raw material."

"'While this argument is only speculative, this research produced an alternative testable hypothesis, setting the basis for future experimental studies.'"

Comment: this study does not help us decide our differences, but it certainly demonstrates how different our brain start is compared to other animals. My bolded portion above is discussing the entire cortex, not confined to the thinking frontal cortex where most of the s/s/c is interlocked.