The skull and the brain in humans evolved from the common ancestor of humans and chimpanzees and it's bigger in humans than in Chimpanzee.
Repeating the questions regarding the evolution of humans from the common ancestor.
Did the skull evolved first to get bigger and next the brain?
Did the brain evolved first to grow bigger then next the skull?
Did both evolved simultaneously؟
Do you think that both were designed to be fixed in place or it just happened
that both evolved simultaneously and it was perfect?
Since it would make no sense to have a giant skull, with a tiny brain? And, obviously, the brain *must* fit within the skull?
They both would have changed size at the same time-- we have examples of Ailments among humans, where the brain-skull sizes do not match, and these are always Bad News-- often fatal. (especially if the brain tries to get too big-- fatal. Google Brain Swelling).
DNA is not a blueprint, in the sense a floor plan tells the builder specific details and measurements to build a house.
No, DNA is more of a set of directives: begin making an arm bud
here. When the arm bud achieves certain attributes, begin a hand-bud
here. And so on.
For example: If you had a way to decode DNA, and read it like a book? No where will you find a way to predict what the fingerprints will turn out to look like, nor can you determine the pattern of the eye's iris or retina. That's not how DNA works.
Even in Identical Twins: They have identical DNA, but each have unique fingerprints, and other fine measurements-- different from their sibling.
So the brain grew and the skull also grew at the same time. It would be very difficult to determine which drove which, but it's a safe bet to presume the larger brain drove the size of the skull, rather than the reverse.
Why? The skull grows to cover the brain, and indeed, is not made of bone until very very late in the fetal development. In fact, infants are born with "soft heads" in that their skulls are incomplete, rather being soft and flexible cartilage instead. This lets the baby exit the birth canal, without destroying the mother.
Early in human evolution, having a Bigger Brain enabled better Heard Behaviors-- many think the principle key is very complex
language. That became possible because of some fine details in the proto-human's throat, nose and mouth.
Once primitive communication skills appeared, it likely drove a selection for individuals with superior skills, over individuals who's brains could not cope.
All hypothesis, of course-- we truly do not know exactly, here.
