1. For your homologous traits provide the following information (25 pts):
a. Briefly describe (not just identify) the two different species that possess the homologus trait. (5 pts)
The tailbone of a human (the coccyx) and the tail of a monkey are examples of homology. The tailbone is called the tailbone because of the shared lineage.
The tailbone of a human (the coccyx) and the tail of a monkey are examples of homology. The tailbone is called the tailbone because of the shared lineage.
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. (10 pts)
The human tail bone and the ape tail share similar bone structure up to the actual extension of the tail from the human body. There are many shared muscle groups between apes and humans in the coccyx region, therefore indicating the two species likely shared a common ancestor but diverged as they evolved. The difference today is obviously that humans no longer utilize a tail.
The human tail bone and the ape tail share similar bone structure up to the actual extension of the tail from the human body. There are many shared muscle groups between apes and humans in the coccyx region, therefore indicating the two species likely shared a common ancestor but diverged as they evolved. The difference today is obviously that humans no longer utilize a tail.
c. Who was (generally, not specifically) the common ancestor of these two species and how do you know that ancestor possessed this homologus trait? (5 pts)
The common ancestor between humans and apes is whichever hominid accomplished the bridge to bi-pedal walking. That was the divergent breaking point in the evolutionary tree.
The common ancestor between humans and apes is whichever hominid accomplished the bridge to bi-pedal walking. That was the divergent breaking point in the evolutionary tree.
d. Provide an image of each species in this comparison. (5 pts)
2. For your analogous traits provide the following information (25 pts):
a. Briefly describe the two different species that possess the analogous trait. (5 pts)
The fins of a bird and the wings of a penguin are analogous traits. One is a bird and the other is not yet both possess fins to navigate a similar environment.
The fins of a bird and the wings of a penguin are analogous traits. One is a bird and the other is not yet both possess fins to navigate a similar environment.
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. (10 pts)
Though the fin of a fish and the wing on a penguin are not evolved from the same ancestor but they serve the same function in their respective environments. The wings and the fins are structures almost exactly alike and are utilized for propulsion in water.
Though the fin of a fish and the wing on a penguin are not evolved from the same ancestor but they serve the same function in their respective environments. The wings and the fins are structures almost exactly alike and are utilized for propulsion in water.
c. All pairs of organisms share some common ancestor if you go back far enough in time. Could the common ancestor of these two species have possessed this analogous trait? How do we know these traits are analogous and not genetically related from common descent? (5 pts)
It’s possible that they shared the trait. Though the mutual ancestor of penguins and fish was likely some type of flying reptile, so the function likely diverged for awhile until the timeline of the penguin lead it to adapt to a water environment from the air.
It’s possible that they shared the trait. Though the mutual ancestor of penguins and fish was likely some type of flying reptile, so the function likely diverged for awhile until the timeline of the penguin lead it to adapt to a water environment from the air.
d. Provide an image of each species in this comparison. (5 pts)
The opening section in both the homologous and analogous areas asked for a description of your species, not just identification of the traits. This would help your reader understand the environment and behavior of the species to better understand why their traits evolved the way they did. Needed to be expanded.
ReplyDeleteIn your first section, you highlight humans and monkeys as your compared organisms. Then in your next section, you compare humans and apes. Other than the point that humans ARE apes, recognize that apes and monkeys are not same thing. Moreover, apes (including humans) do not have a tail. This is one of the defining traits of the ape classificatory group, that they are lacking a tail. Monkeys, on the other hand, all have tails. You needed to stick with the human/monkey comparison because with human/non-human ape comparisons, you are comparing two species that don't really differ much at all in the trait.
That said, if I recognize that you probably meant to use "monkey's" here, you are correct in your description of the structure, but can you discuss function? Some monkeys have prehensile tails (New World monkeys) and others don't (Old World monkeys) so this needs to be kept in mind during the discussion.
The discussion of function is also complicated by the fact that scientists still aren't sure why apes (including humans) lost their tails. It could be that they just weren't using them and lost them due to disuse. It is also possible that there was a positive adaptive selection pressure, some advantage to having a shorter tail, that pushed apes in the direction of being tailless. We don't know, but I wanted you to be aware of this debate.
With regard to ancestry:
"The common ancestor between humans and apes is whichever hominid accomplished the bridge to bi-pedal walking."
No. "Hominids" are defined as only being in the human evolutionary line, not apes in general. They arose after the split from the non-human ape line and have no influence on ape evolution (or monkey, if that is what you actually meant).
If you were comparing tailed monkeys with tailless humans, then you need to go back to early primates, about 25 mya, to find the common ancestor of both and we know from the fossil records that this organism did indeed have the tail, so that was the ancestral state. The loss of tail is the derived ape trait. This is the information we need to know to confirm that these traits are homologous.
"The fins of a bird and the wings of a penguin are analogous traits."
I had to read ahead and then I realized that you problem meant the fins of FISH? Not a bird? I wrote a long correction and then had to delete it when I realized that you have the right idea, just the wrong name in that first sentence. Edit!!
Good description of the analogous traits in terms of their similarity in function.
Regarding ancestry, the ancestor was much farther back than a reptile, and I'm not sure if you are arguing for analogy or homology. Remember that if these are indeed analogies, at least one organism will evolve these traits independently from the other. That is required for analogy.
To clarify, the common ancestor of the penguin and fish is an archaic fish (penguins are birds who arose from reptiles, who arose from amphibians, who arose from fish), who did possess these fin structure and also passed that trait onto extant fish species. So the question is, did the penguin also inherit it's fin from that common ancestor? As you point out, penguins are birds, but let's take that information further to address this issue. Penguin "fins" are actually derived bird wings. Birds evolved wings when they split off of their reptilian ancestor, long after the split with ancient fish. This provides us with the evidence we need to confirm that this trait did evolve independently in at least one of these organisms, making these traits analogous.
Good images.