This week reviewed many hominin traits that gave us insights into our past biology/behavior, which has also given us insights to our own human evolution. One trait that interested me was brain size. Compared to our brain size now, past hominin species had smaller ones. This trend in increase of size shows how we have advanced in our learned behaviors overtime. As we have become more complex in our “tool making” and language skills, we have become more reliant on them. Because of this, not only has our brain size increased, it has increased largely compared to other parts of our body that may have decreased in size in complexity and/or size overtime – such as our canines and length of our arms.

Another trait I saw was the size of canines. Over time the size of our canines have decreased (compared to past hominin species). Much of this change also has to do with the change of our environment that has also caused a change in how we prepare/consume our food. We can now prepare our food in consideration of how we eat it. We don’t have to rely on large canines because we don’t have rip and tear a large portion of our food, so it wouldn’t make sense in keeping such large ones. But not only with food, this “primitive” trait of larger canines were diminished in modern humans because it wasn’t needed in our environment (for specific reasons I am unsure of).

The third trait I was interested in was bipedalism. This transition was seen when there was a transition in the environment – a time where most species of ape died off. But despite this, the trait had poor preservation. Many hominins, such as Sahelanthropus, Orrorin, and Ardipithecus had “primitive” straits (like longer arms) and derived traits (bipedalism). In the first steps of this transition, you see that these apes still relied on their “primitive” features – but each of the hominin species relied on bipedalism in different ways – based on different evidence given by their skeletal remains. In the present, you can observe the reliance on “primitive” and derived traits among human and non-human primates. A lot of this can be because of the different environment that we have lived in. Spider monkeys for example would rely on their arms for transportation more because of their environment, it would be a burden to worry about the hassles of predators and forest debris on the ground, so it would make more sense for them to rely on their “primitive” features more than their “derived” features. Humans on the other hand have evolved to rely on their “derived” features (bipedalism) for transportation. We have the ability to change our environment to suit our needs so “primitive” features don’t need to be relied on.

Fossilized skeletal remains of early human ancestors may not be able to one hundred percent show us how we behaved in the past, but it can help also give us insights to how we looked. Features such as the size of our canines and length of our arms, for example, show us how our diet/locomotion have changed overtime. Trends, such as the change in shape/size of skeletal features, can show how hominin species have changed overtime and thus show how we have as well.