1. Two different species that possess the homologous trait would be a bats wing and a human arm.
2. Describe the homologous trait of each species, focusing on the differences in structure and function of the trait. Why do these traits exhibit differences between the two species?
The human arm and a bats wing is significantly different in appearance but they in fact share the Humorous, Radius, Ulna, Carpals, Metacarpals, and Phalanges. The difference in the way we use our arm is to grasp, drive, write, and basically perform daily functions. The bat will use his wings to glide in the sky and fly around, they can also wrap their wings around insects or fruit to eat.
3. Who was (generally, not specifically) the common ancestor of these two species and how do we know that ancestors possessed this homologous trait?
The common ancestor of these two are mammals, their ancestor would have had this same limb causing them to have the homologous trait.
4. Images 🦇💪
Analogous Traits
A. Describe two different species that possess the analogous trait- Would be the human eye and the octopus eye.
B. Describe the analogous trait of each species, focusing on the similarities instructor and function of the trait. Clearly explain why these analogous traits exhibit similarities between the two.
The octopus and human eyes both have a "camera-type" morphology. We share an iris(pupil) which controls the amount of light reaching the retina, a lens which helps focus light and images, and a retina which converts incident light into signals that are carried to the optic nerve to the brain. The one thing that I believe the octopus has on the human eye is the "blind spot." The human eye has a blind spot in the optic disk within the retina where there is no image detection therefore the term "blind spot." The octopus does not have this which would make its eye a better structure than ours.
C. All pair of organisms share some common ancestor if you go back far enough in time. Did the common ancestor of these two species possess the analogous trait?
I do not think that these two shared the same ancestor, at some point in time in their environment it causes them to shift into having the camera type morphology.
D. Images 👀🐙
Hi Natalie~ I found the analogous of the human eye and octopus eye really interesting. I had no idea that they were so similar and yet the octopus eye would allow it to see where the human eye couldn't. (blind spot) Great information!
ReplyDeleteThe opening prompt asks for a description of both of your species. Short on this for both your homology and your analogy sections.
ReplyDeleteGood discussion on differences in function for your homologous pairings, but how are these differences in function reflected in differences in structure? I can see some of those differences in your images, but this needed to be outlined in your writing.
Okay on ancestry, but how do we know that ancestral mammals had this trait? Fossil evidence?
The eye is a fascinating example of analogy, as this structure has evolved independently several times on our planet. Good choice and good description.
"I do not think that these two shared the same ancestor"
Ah, but as explained in the guidelines, all organisms share a common ancestor if you go back far enough. So the question remains as to whether that common ancestor possessed this trait. We have a couple of pieces of evidence that the common ancestor didn't. One is phylogenetics, which indicates that the genes controlling these two versions of an eye are completely different, indicating that they share different origins. The other evidence is what you mentioned. The design of these two eyes are backwards from each other. It isn't possible to have a rudimentary structure that gave rise to both forms, since their base structure is so different.
Good images.
Natalie,
ReplyDeleteI found your section involving the eyes very interesting as well. I never would have thought. I find it so amazing how you went that route. Good job!
Hi Natalie,
ReplyDeleteI have to say I found the traits you chose very interesting especially when you went into detail about the analogous traits of each species. As Talor mentioned above I find it pretty interesting and genius that you decided to go the wrote of talking about eyes. Overall I must say this is a great post. Keep up the great work!