For Homologous:
Briefly describe the two different species that posses the homologous trait.
- Gorilla and Chimpanzee. Both chimpanzee’s and gorillas have thumbs that are very similar, along with climbing trees and a similar diet.
B. Describe the homologous trait of each species.
- Gorilla’s are much bigger in size and a lot stronger compared to chimpanzee’s. Both are vegetarians, but while the gorilla feeds mainly on stems and leaves, the chimpanzee eats mostly fruit. Gorilla’s can climb trees but chimpanzee’s spend most of there time in tree’s.
C. Who was generally the common ancestor of these two species and how do you know that ancestor possessed this homologous trait?
- The ape was generally the common ancestor of these two species. I know the ape possessed the homologous trait because homologous traits are evidence of shared ancestry, and they share a genetic code.
D.
For Analogous:
A. Briefly describe the two different species that posses the analogous trait.
- Dolphins and Sharks. Although they may share the same shape, underneath their skin, sharks and dolphins are very different.
B. Describe the analogous traits of each species.
- Sharks' and dolphins' similarities such as their body’s shape, their fins, and flippers are analogies. Traits that each evolved independently. Structure and function include, sharks skeleton is made of cartilage while a dolphins skeleton is made of bone. A shark uses its gills to get oxygen from the water in which they swim, dolphins go to the surface and breathe atmospheric air in through their blowholes.
C. Could the common ancestor of these two species have possessed this analogous trait? How do we know these traits are analogous na not genetically related from common decent?
- The ancestor could have possessed this analogous trait. The tail fins and dorsal fins are analogous because the terrestrial ancestor of the dolphins did not have a dorsal or tail fin.
D.
You make some very valid points in your comparison and I have to agree with them. Just reading about your comparison of the dolphin and the shark has made me learn some new and interesting facts about each species. You could have explained a bit more of why did the shark and dolphin develop a dorsal or tail fin if it is not a homologous trait. But nonetheless, good job!
ReplyDeleteCan you explain what specific trait you are comparing in your homology section? You start off by mentioning the thumb but don't talk about it in your second section and the traits you do mention there are generalized. You needed to pick one specific physical trait that was shared by two organisms due to common descent but exhibiting key differences due to differing environmental pressures. The thumb might have worked if you had explained how the gorilla and chimpanzee thumb were structural and functionally different and why.
ReplyDelete"I know the ape possessed the homologous trait because homologous traits are evidence of shared ancestry, and they share a genetic code. "
True... but we are trying to provide evidence that traits are homologous. Using the homologous traits to support common descent to support homology is a circular argument. You needed to provide independent evidence that the common ancestor of these organisms possessed and passed on the trait in question to the descendants. That would demonstrate that similarities were inherited while differences were the result of differing environments.
Good choice of your analogous traits. Can you explain why these similar traits arose in dolphins and sharks?
"The tail fins and dorsal fins are analogous because the terrestrial ancestor of the dolphins did not have a dorsal or tail fin. "
Ah, now you are on to something. Yes, we need to find that at least one of these organisms evolved this trait independently from the other to confirm analogous status. Dolphins arose from land mammals with no fin structure. That confirms analogy.
Good images.
As far as the thumb goes, Chimpanzee's and Gorillas have inherited a more primitive hand structure. Gorilla hands have five fingers. Including an opposable thumb, much like us. This is an example of homologues because it shows that from our shared ancestor, we inherited this trait. The ape and us share this because the hand is one of the most distinctive traits of between us both.
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