The basis of all life on earth runs on the concept of natural selection. The human race, along with every other species, is constantly evolving and adapting to its surroundings. There are countless ways that this can be observed, but some of the more notable ones include our biological traits like our heads and the length of our appendages and the development of our cerebrum. All of these things have changed over the thousands of years that our ancestors date back to; this is attributed to the fact that those traits that have been selected to remain are biologically superior and/or lead to more successful reproduction and continuation of the species.
Throughout the time it has taken for our species to get to where it is today, we have changed in physical appearance quite a bit. First, we began by walking on all fours. Skeletal evidence shows that the foramen magnum in the skull was on the back of the head, signifying a being that walked on all fours because the spinal cord went backwards horizontally. In order for this to work in tandem with the rest of the body, the arms must be very long so as to reach the ground comfortably and the bones in the hand have to be incredibly strong, as the knuckles have to bear a substantial amount of pressure. This is quite obviously substantially different from what we have evolved into. Since bipedalism was deemed more efficient, the foramen magnum had to relocate to allow the spinal cord to extend down vertically. The legs had to become longer to reduce caloric expenditure and the arms became shorter in response. The knuckles were able to develop with more dainty bones and therefore increase dexterity for hunting and gathering. Each subtle difference made over time increased the overall life expectancy or reproductive potential for our ancestors in some way, shape, or form.
Another way that our bone structure has differed over the years has been the shape of our skull. In the beginning, there was a much smaller space for the brain in comparison to what each of us has tucked away in our heads today. This is due to the fact that our cerebrum, the area of the brain responsible for thought, action, and intelligence, has grown considerably. This is interesting to me because not all animals are naturally selected to improve intelligence. If they were, then there would be more than just our species that operated at our level of brain capacity. Even some of the species in our lineage regressed intellectually as a result of evolution such as the homo floresiensis. Why is it that our cerebrum has grown so considerably in comparison to our cohabitants?
This class has taught me more about evolution than I have learned in each and every course I have ever taken, a fact that I find very disappointing. Not only has the class opened my eyes to a whole new world of possibilities pertaining to where we come from, but it also has given me insight on where we may end up in the future- a skill that I will be able to carry with me throughout my career.