a. Briefly describe the two different species that possess the homologus trait.
The human being and the dolphin possess the homologous trait. The structure of their features comes from common ancestors.
b. Describe the homologus trait of each species, focusing on the differences in structure and
function of the trait. Why do these homologus traits exhibit differences between the two
species? Make sure your explanation is clear and complete.
The homologous trait of each species are the forelimb of the person and the flipper of the dolphin. In both mammals the fin and the arm are composed of the "five-digit forelimb" they are the same in both humans and dolphins but serve different purposes. The dolphin fin is used only for the dolphin to swim and the human are is used to be grabbing the items they need and using it to reach for items through out the day.
c. Who was (generally, not specifically) the common ancestor of these two species and how do
you know that ancestor possessed this homologus trait?
Amphibians were the common ancestor of these two species. I know that the ancestor possessed this homologous trait because the majority of mammals today have the same "five-digit" limb structure.
a. Briefly describe the two different species that possess the analogous trait.
The parrot and the butterfly both have the analogous trait of having wings.
b. Describe the analogous trait of each species, focusing on the similarities in structure and
function of the trait. Clearly explain why these analogous traits exhibit similarities between
the two species.
The analogous trait of each of these two species is the trait to fly. The structure of the wings is not exactly the same because the parrot has feathers and the butterfly has scales but the wings serve the same purpose which is the purpose of taking flight. The analogous traits exhibit similarities between the two species because they have two different sets of structure of the wings that serve the same purpose which is the need to fly to be able to survive.
c. All pairs of organisms share some common ancestor if you go back far enough in time. Did
the common ancestor of these two species possess this analogous trait? Why or why not?
The common ancestor did not possess the analogous trait because going back far enough in time the older ancestor of a bird was a reptile that was not able to fly and did not have wings therefore, if they did share an ancestor the ancestor would have been more than likely lacking the analogous trait.
The "description" of the organisms in your homologous pairing needed more description.
ReplyDeleteGood explanation of your homologous traits and good connections made with structure and function.
You are on the right track with regard to ancestry, but you don't need to go all the way back to amphibians to find the common ancestor. Humans and dolphins are both mammals, so the common ancestor was an ancient mammal who possessed the ancestral trait inherited by both modern descendents.
Again, "description" doesn't mean 'identify".
Good connection made between similarities of both structure, function and environmental pressures.
For an ancestor to be "common" between insects and birds, you would have to go back much farther than the reptiles, but is that necessary to know if this trait is analogous? Birds developed wings after their split from reptiles (or perhaps 'during'), and this means wings developed independently from insects or their common ancestor. That is sufficient to know that these traits are not of genetic origin and are therefore analogs.
Good images.