Homologous vs Analogous traits.
Homologous
Orangutans are one of the largest primates with males reaching heights of up to 5' feet and a weight of nearly 200lbs. Their arms are 1.5 times the length of their legs and have feet that more closely resemble their hands, providing them with 4 limbs which they use to walk, climb, eat, and manipulate objects. Humans are the only living species of homo sapiens. Humans have an average height somewhere between 5'6" to 5'8" and an average weight of around 200lbs for males. Humans and Orangutans share many physical traits with each other including teeth. Both humans and orangutans have 32 teeth which include incisors, canines, premolars, and molars. That is where the similarities end however has the shape of the jaw and the teeth themselves differ between the two species. Orangutans have a larger rectangular shaped jaw when compared to a human, along with generally larger teeth, especially the canines. This is due to the main food groups of Orangutans which is primarily composed of fruits and vegetation. The larger jaw and teeth aid in the breakdown or large plants and for getting into fruit protected by a shell. Humans have developed a smaller, parabolic shaped jaw and smaller teeth as our diets are more well-rounded and presented in a more manageable size. Orangutans and humans come from the Hominidae family, fossils from the family such as those of great apes have a tooth structure that closely resembles that of humans and orangutans.
Anagolous
Penguins are flightless birds that have adapted well to swimming. They have short wings and a tail which they use to propel and maneuver under water however. While on land however they rarely use their wings and their tails help with balance. Fish are water based vertebrates which have fins for limbs. Both have fin-like structures which they use for the same purpose, moving and navigating through water. Fish have evolved over the past 530 million years, they have developed fins as a need for basic survival. Penguins however evolved from birds, however interestingly enough there is still a debate alive which asks if penguins evolved from flying birds or from a non-flying ancestor.
Hello Thomas,
ReplyDeleteI learned a lot from your blog post, specifically from all of the details you included when describing the orangutans. Although humans and orangutans look very different, their characteristics and actions really show a lot of similarities. I find it interesting that you chose to specify on the trait of the jaw. It was a unique way to describe their homologous identities. It is very easy to tell someones emotion just by looking at their lower part of the face including their jaw. I don't think any other animal has the ability to show emotion with the bottom half of their face like orangutans and other monkeys.
Hello,
ReplyDeleteYour blog post was well researched and put together. I like how you stuck to the your interest in orangutans haha. I find it interesting that you chose humans and orangutans instead of any other mammal with a jaw and similar features. In my research on penguins it shows that recently they found that penguins actually derive from a not flight animal that used to hunt in waters. Apparently where they evolved to fit the aquatic environment more.
Great images!
ReplyDeleteVery good homologous comparison. Good opening description of the two species and good discussion on the relationship between the structure and the function of the teeth and jaw. Well done on using ancestry to confirm homology.
The only point I would like to add is to ask if diet is the only influence on dentition? It does seem logical to assume diet will play a role, but that doesn't mean other factors won't come into play as well, and this question actually comes up in an assignment next week. Think in particular about those canines... can they be used for something other than eating? What about defense? Or threatening predators or rival mates? Is it possible the could be the product of sexual selection, with females choosing males with larger canines? Think outside the box on this.
Regarding your analogy section:
Good description of your species and good discussion on the similarities in function that drove the convergent evolution that produced these similar traits in very different species.
Regarding ancestry, you don't actually discuss the trait itself. How does the information you provide confirm that these traits arose independently from each other and are therefore analogous traits? You are correct that penguins "fins" are actually derived bird wings. That is the key here. The fin structure in penguins wasn't inherited from the common ancestor with fish (which is just archaic fish) but evolved much later, independently, after birds split off from reptiles. That is the information we need to confirm analogy.