Introducing the brain: fast evolution explanation (Introduction)

by David Turell @, Tuesday, May 12, 2020, 00:56 (134 days ago) @ David Turell

Another view of how fast it happened:

https://www.allaboutscience.org/evolution-of-the-human-brain-faq.htm

"As with other complex biological features, scientists explain the evolution of the human brain through natural selection. However, the human brain presents some unique challenges that must be answered through slightly different methods. There are aspects of the brain of homo sapiens that do not fit Darwin's usual pattern. The time scale allowed for significant change is shorter. The mental capabilities of humans are far above other organisms. The unique nature of man puts our brain in a class by itself.

***

"Scientists have experienced problems when applying the normal methods of evolution to the human brain. Paleontologists and neurologists have noted that there is little to no notable difference between the brains of modern humans and so-called Neanderthals, other than a slight change in size. Given the supposedly significant differences in intelligence, social structure, and physical features, this seems strange. Those studying this field admit as much. The coordination required between the brain and the body is another. The development of the human brain is one of the biggest unsolved mysteries for evolution.

"The response used by scientists to explain the evolution of the human brain involves a "fast evolution" scheme. Researchers at the Howard Hughes Medical Institute concluded that the human brain evolved very rapidly. Their research led them to believe that there was considerable "selection pressure" to evolve the brain into a larger, stronger unit. As human society became more sophisticated, the advantage of a larger brain became more pronounced. This caused the evolutionary process to accelerate, resulting in a quick progression to modern man.

"There are some unanswered aspects to these theories, however. As with most other evolutionary studies, there are plenty of reasons given for why a larger, stronger brain is useful, yet no actual biological or physical explanation for how it occurred. It is important to realize that modern science has never observed a beneficial, inheritable mutation that causes a permanent change in a species. Variations from a norm have survived a few generations, but then have swung back to the original form.

"The idea that the usefulness of the brain caused evolution to accelerate also seems improbable. If the advantage was very strong, it would seem more likely to see a very clear, steady, uninterrupted evolution. Just because a feature is useful should not make a mutation more likely. To assume that mutation occurred more frequently because the larger brain was "needed" implies intent and intelligence behind the process.

"Finally, aligning the development of the brain with the development of the body poses a massive problem for evolutionary scientists. Simply looking at a possible evolutionary event brings the dilemma to light. Imagine a mutation, or series of mutations, that improve the eyesight of an organism. For the brain to be able to process this information, it either must evolve after the eye, before the eye, or at the same time." (my bold)

Comment: Rather than coordinating with the eye or other sensory structures, my previous point is more important to consider, that the brain enlargement has to coordinate with bigger skull (bone) size and a necessary enlargement change in the female birth canal (pelvic bone) to accommodate the bigger baby skull (bone). Not by chance was Adler's point also.


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