Blog 5: Fossil Record

Hominins are members of the ape species that are bipedal, and remain bipedal. This means that they use only two legs for walking instead of walking on all four limbs, like modern apes do. Hominins have been seen for at least 5 million years, although the exact start of bipedalism is still unknown.

One of the most interesting traits of the early hominins was seen in the Laetoli footprints. These footprints were created at least 3.75 million years ago. These footprints, found in Laetoli, Tanzania show bipedalism. The footprints also indicated that there were two hominins walking together next to each other. This is seen from the non-divergent big toe, heel strike and the developed arch. The heel strike means that the hominins landed on their heels first, and then pushed off with their toes. This is incredibly similar, even the same, to how modern humans walk today. This means that the strides are similar to human strides. This illustrates a trait that can be seen today in modern humans, showing direct relations to earlier hominins, as well as specific and direct evidence for evolution.

Another incredibly interesting trait comes from A. garhi which has features that are similar to modern humans, or the genus Homo. The teeth are very similar. Both of the A. garhi genus and the genus Homo have large front teeth. This is the opposite of other types of hominins, like the Paranthropotus, which have incredibly large back molars and very small front teeth. Both of these genus also have similar premolar shapes. In addition to that, the ratios of arm and leg length are, again, quite similar to the modern genus homo. This enforces the idea of the bipedalism that has already been seen for several millennia.

In looking at traits of hominins, it is very easy to see evidence for human evolution. As mentioned in the video, the majority of species and genus tend to die out because of mal-adapted traits. However, in looking at genus that have evolved and have been able to pass on their genes, evolution becomes clear. Modern humans are most similar to those genus and species which have been able to survive the longest and been able to pass their genes on. For example, Paranthropotus, who I have mentioned before, had huge back molars and tiny front teeth. This is very unlike the teeth that we have today. These teeth had very strong pressure and created a very strong jaw, but the energy needed to use them was not enough to justify having them. This meant that this genus died out because this type of set of teeth was not entirely useful. This is why this set of teeth is not seen today.

Fossilized skeletal remains of early human ancestors can help anthropologists reconstruct and learn from the past because it is a very obvious way to see what kinds of traits were seen in the past that are seen today as well. Fossilized remains of things such as skulls can be compared to modern human skulls today to see similarities and differences. They can also be compared with each other to see the evolution of things such as the size of the brain. This is why skeletal remains are so important.

2 thoughts on “Blog 5: Fossil Record

  1. I agree with your thoughts on natural selection. It seems the genetic traits of early hominids that died out were not needed for survival and the ones that survived we possess very similar qualities. It reminds me of Darwin on how he thought natural selection was the most reliable factor in passing on desired traits, for future generations to guarantee survival. Early hominids must have possessed these traits and we have eventually inherited the best suitable for survival. You brought up examples like teeth, large teeth expanded to much energy and we did not need them, so they died out. You also mentioned arm and leg ratio, since many hominids have similar proportions with modern day humans, bipedal-ism must have been an evolutionary advance a long time ago. That advance was very important to the advancement of modern day human traits. Another factor that proves natural selection in human evolution.

  2. As you mentioned human evolution has come a long ways since our early ancestors first started walking upright. Along this long path of evolution our species has had to adapt and change several traits in order to ensure the survival of the species. The best and most effect way this was done was by passing on the genes to the next generations as you stated. However it wasn’t just ensuring that genes were passed on to the next generation. It also involved passing on the right genes so that the next generation was also successful and able to survive and then therefore pass on its genes as well. Your example of Paranthropotus having too big molars and therefore possibly costing it to be able to pass on its genes to the next generation is a good example of having the right traits to pass on was essential.

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