Last night, I recorded (while looking at Mars with friends) a fascinating science program about the evolution of the human cranium (and thus his brain)...
The first bone from the cranium to form in a human embryo
is the sphenoid bone (it looks like a butterfly and is located at the base of the skull).
Anne Dambricourt has noticed five sphenoid flexing since the past 60 million years in the lemurians, then the apes then the hominids (40 million, 20 million, 6 million, 2.3 million and 160,000 years ago)...
Anne is in contradiction with paleontologists (like Yves Coppens) who think the cranium evolution is caused by the environment and thus is exterior to the living beings.
The flexing of the sphenoid each time resulted in a more voluminous cranium but also a narrower jaw!
In the program, an orthodentist was also studying the same thing (she wondered why more and more children needed orthodontic treatments and the culprit turned out to also be the flexing of the sphenoid).
Philip Tobias who agrees with Anne, says: extinction of species are the rule, survival is an exception. Perhaps the sphenoid flexing is a success sign for evolution (at least so far).