Hominin traits can be classified as “primitive traits” and “derived traits”. Primitive traits are ape-like traits such as quadrupedalism, small brains, and long arms. Derived traits are hominid-like traits such as small teeth, bipedalism, and shorter arms.
Bipedalism is an important hominin trait. Bipedalism is what defines hominins. The evolution of bipedalism suggests that there was an environmental transition that, gradually, forced organisms out of their traditional arboreal environments. The process of evolving bipedalism reasserts the modern human terrestrial lifestyle. We are not arboreal creatures. I can affirm that I would probably fall out of a tree, if I could even climb one. Our bodies are not currently built to survive life in the trees. Another factor, besides modern historical patterns, that suggests humans would not succeed in the trees is that we don’t have an abductable big toe. This derived trait is first recorded in the Australopithecus afarensis species around 3.9 million years ago. This is the Lucy species. An abductable big toe helps organisms to grasp with the foot. This would be a great trait to have in arboreal environment; however, humans do not exhibit this trait. Another trait that would place hominins in the trees would be long arm length in comparison to the body. Having longer arms proves to be more advantageous in arboreal environments. We see a modern-looking arm to leg length ratio first appear in the Australopithecus garhi species around 2.5 million years ago. Comparing the fossils of more recent hominins to older hominins helps anthropologists pick out the differences between us and arboreal creatures. This research in correlation to paleoecology unlocks the process of the environmental shift from woodland to colder temperatures.
With the exception of Paranthropus, teeth size seemed to get smaller as time went on and as hominins began to exhibit more derived traits as opposed to primitive traits. Large teeth are a primitive trait because teeth wouldn’t only be used for eating; they were also used as an intimidation tactic. As the organisms became increasingly bipedal, their arms and hands were freed up and could become more effectively utilized. In the lecture it was described as if two humans were in a fight, we wouldn’t even think to initiate it teeth first; we’d throw a punch first. That made me laugh at first, but it really sheds light on the versatility of primitive dental structures. Small front teeth and larger molars in the back also reflect a change in diet. Gradual changes in the diets of these organisms reflects gradual changes in their environments. We can also see this with modern humans on a shorter scale. Because of globalism with the human population, a single city now has access to so many different foods and a much more complex, diverse diet, than they would have had 200 years ago. While modern humans aren’t necessary showing as crazy of an evolution in their dental structure as these early hominins did, researchers can study these early environmental shifts through the diets of our ancestors.
What I find most fascinating about the evolution of these specific traits is that it all goes back to the environment. Organisms adapt to the world around them. By studying the early environmental shifts, maybe scientists can helps us to understand the current climate crisis and the kinds of effects it may have on us as a species.
First of all, I really like how you initially introduce the two categories of traits, I feel like this leads to very consolidated essay organization. Your explanation of each of the traits in relation to how they correlate with the environment the organism lived in is very cohesive and thorough. I really liked reading your post because it was very matter of fact, but at the same time it didn’t feel like it wasn’t put together like a list. Environmental changes had a huge impact on the physical appearances and adaptations of the creatures we study and I think the emphasis you put on this was great. Personally, I thought you very adeptly described each of the traits that were needed for life in trees and how they are no longer needed for us now because we live solely bipedal lives on flat land.
I think you did a very good job writing your post. I really like how you mention that hominins were a mixture of derived and primitive traits and set up a timeline to show the mosaic evolution of hominins. I also found it interesting that you mentioned how arm length has changed for hominins over time. In my blog I only focused on traits that had a direct impact on hominins becoming more and more bipedal. However, I think it was really smart to show how other traits changed, like the length of arms and size and shape of teeth, as hominins became less and less arboreal. I also liked how you explained how bipedalism led to an increase in brain power, this was a little confusing to me in lecture, but I understood your explanation.
I enjoyed reading your post this week! I also really was interested in bipedal and talked about it also! It is crazy that based on the environment forced evolutionary changes! I like how you mentioned about you would fall out of a tree if you tried. It is crazy to think that was our only way of really getting around because bipedal hurt us when walking and we were forced to swing in the trees. I also talked about the teeth and how they got smaller over time and how they were used for different purposes back then compared to we just use them now for eating mostly and looks! I think you mentioned everything good in detail. As mentioned in a comment above, I was also confused about some things in lecture but after reading your post with examples and hearing it a different way, I understood it way better since lecture throws so much at us at once!
Hi! Thank you for sharing the information that you found interesting this week and your thoughts. You did an amazing job at getting all of your thoughts written down in this post and formatted your words perfectly. In my blog post, I mentioned the teeth only merely, though I did enjoy how you gave a whole paragraph just for the development of how primates used their teeth. Especially the analogy saying how we, as humans, are more likely to instinctively, in violent situations, throw punches, rather than utilizing our teeth which our primate ancestors did. I also talked a lot about the importance of bipedalism and how our bone structure differs from bipedal apes due to our long, proportional limbs which inhibits us from living in trees and allows us to walk long distances.
Hi! I enjoyed reading your informative and introducing two traits of primates in terms of bipedalism and teeth size. I see a lot of people have discussed about these two traits that are really important to survive in the wilds. These two traits have been evolved for such a long time to adapt hominins better in the environment. Hominins become more bipedal as time goes and teeth become evolved because of change in dietary patterns. I liked how you compared it to change of other traits in time as well.
Thank you!
Hi Sam, I really enjoyed reading your post for week five. We talked about the same traits each week, so I liked reading your thoughts! I really liked the way you wrote your post this week. I feel that your layout was very simple and easy to follow, and you introduced all of your topics really well and provided a lot of background information before going into too much detail. On the quiz for this week, one of my questions was “where did bipedalism evolve” (talking about which environment) and I honestly could not find it anywhere in the lectures but ended up getting it right. I wish I read your post first because you explained it so well! Thanks again for your well-written post!
Hey! I really enjoyed your post. I think you explained the traits that led to the development of humans was really clear and thorough. I really liked how you explained primitive and derived traits at the beginning. It gives a start as to what the rest of the paper will be about. I also, talked about bipedalism and how big this trait was because when thinking of animals we don’t think of them as being bipedal.
I also, liked how you talked about the evolution of teeth. How teeth were used in the past and how they evolved to what are being used now for and that’s to eat.