Before this week, I had no idea I would have to type so many long, difficult words in order to take notes about the multiple groups that describe our evolutionary phases. Although the names of these groups took some getting used to in order to become familiar with, I can now say a lot has sunk in from these lectures, and I have a much better understanding about our modern biology through learning about specific traits developed over long periods of time.

These lectures covered a great amount of phenotypic traits that have constantly been developing in hominins due to our surroundings and primary usage, in which we can connect to our physical traits today. It’s basically as if our biology has been leaving reformed bread crumbs throughout our ancestry which can make tracing fairly straight forward, as long as bones have been preserved well. Important traits I will be touching on found throughout various hominin groups are dental anatomy and skull/brain structure.

Beginning with an earlier group, the older species of the Ardipithecus group, Ardi Kadabba, showed relatively large ape-like canines (but more like incisors in structure), while the later species, Ardi Ramidus, have slightly smaller canines that resemble humans’. Smaller canines and extensive faunal and flora are associated with the Ardi Ramidus, and seeds, Colobine monkeys, and kudus common in African woodlands and forests also support the hypothesis that Ard. Ramidus lived in a forested environments. The Ardipithecus group also begins with a small ape-like brain, but contain a derived feature that we assume makes them bipedal — foramen magnum under skull. Found in late pliocene hominin diversities, Robust forms prove major developments within the dental anatomy that is so different that they get their own genus: Parenthropus. Crests on their skulls are attachments for muscle that are used during chewing. Massive premolars, molars, and small front teeth (to make room) are evident, as well as non-projecting canines with no diastema. Within later Gracile Australopithecines, they are found to have large incisors (unlike robusts), which suggests a more diverse diet; however, they also have large back molars like robusts. When comparing brain sizes of the Robust and Gracile groups, they are fairly similar, but both in ape-like range. The average size of the Robust is around 500 cc, while the Gracile average size is around 450 cc. Later down the line, we find that the A. Gahri have derived features similar to Genus Homo where they have large front teeth and a similar shape in the premolars. The head structure of the Gahri most resembles Homo, however, they still had a chimp-sized brain (450 cc’s) and some other primitive features.

Fossilized skeletal remains of early human ancestors can help anthropologists determine the age of certain fossils through relative or chromatic dating, which then can help place evolutionary changes within the context of specific environmental conditions. Finding the age of fossilized skeletal remains is the key to understanding the course and rate of evolutionary changes. Paleoecology is an important study that helps us reconstruct the prehistoric by answering questions that help us learn more about our past such as: what animals were present? what plants were present? what types of water sources were present? what was the temperature? was there a lot of seasonality?