What can I figure out by looking at skulls and their features in terms of evolution?

By looking at the morphology in different skeletal fossils, you can create a phylogenetic tree to try to find the closest relationship among a group of organisms.





For example, say you have 3 primate skulls. Two have a sagittal crest (ridge on the top of the skull that muscles attached to for stronger mastication), and one is missing the sagittal crest. You can probably deduce that the two with the sagittal crest are more closely related and you can draw a phylogenetic tree with maximum parsimony. Just pick out distinct features and you can group them together.





However, it's not as accurate as creating a genetic tree with the help of genetics, but it certainly can bring you to a better understanding of evolution and the organisms' relationships to one another.What can I figure out by looking at skulls and their features in terms of evolution?
So much! Its probably THE most important thing as it tells us what they ate...


We know the trend in teeth is 5 to 4 cusps on teeth and smaller teeth...this indicates that food has become more processed (eg cooked) and less tough and more meat based.


Teeth between sexes have become similar, rather than males having large canines, this indicates the change in social structure and how males work in the group.


The size of the jaw is getting smaller (and so have less teeth..or at least wisdom teeth are a problem or not even present in some people today)...the muscles that attach the jaw have changed from the large saggital crest on the top of the head to a more rounded top skull.


General size of the brain has got bigger over time (exception is the Neaderthals which had a larger brain that us) so we can see that trend in skulls.


Another thing is the devlopment of speech and language and skull casts can show the development of these areas (as bumps etc in the skull), in particular the Broccas area. Also the devopment of the frontal lobe which has resulted in H.sapiens having a flat or rounded forehead rather than a sloping back forhead in more primative types.


The brow ridge has become less prominant in us and can see that changing and the chin has become more prominant.





These are the main things, there are also other things like the zygomatic arch (cheek bone), nose shape, muscle attachements, shape of the skull, position of the foramen magnum (for bipedalism), size of particular muscles and the teeth.