Analogy & Homology
a. Briefly describe (not just identify) the two different species that possess the homologus trait. (5 pts)
Per the name of my blog I obviously have to go with Gorillas and subsequently humans. Specifically, we both five phalanges that are a direct result of a common ancestor. We also both have opposing thumbs and walk upright, again both as a result of our common ancestor.
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)
Gorillas have denser bone structure and larger extremities in their hands and feet. This is because gorillas use their hands and feet to climb and their extremities must be able to support their larger frame and withstand the pressure and force they are asked to endure. Also they do not walk as upright as humans because they also use their hands for walking.
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). This is an age old argument but from all the scientific research that I have seen, humans and apes both evolved from Lucy. The skeletal remains of Lucy indicate that both humans and gorillas share common skeletal structure with this ancestor
d. Provide an image of each species in this comparison. (5 pts)
Gorilla Hands Human Hands
a. Briefly describe the two different species that possess the analogous trait. (5 pts)
Fish are aquatic creatures who have an ancestor that comes from the sea while penguins have an ancestor which are fowl. They both share fins as an analogous trait which are not from a common ancestor.
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.
Both penguins and fish have fins which allow them to navigate in the water. They are similar as they both protrude from the sides of their body which gives them the ability to swim.
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)
Penguins evolved from more ancient penguins which came from Jurassic birds that could fly at one point while fish evolved from ostracoderms, small jawless prehistoric fish.
d. Provide an image of each species in this comparison. (5 pts)
Per the name of my blog I obviously have to go with Gorillas and subsequently humans. Specifically, we both five phalanges that are a direct result of a common ancestor. We also both have opposing thumbs and walk upright, again both as a result of our common ancestor.
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)
Gorillas have denser bone structure and larger extremities in their hands and feet. This is because gorillas use their hands and feet to climb and their extremities must be able to support their larger frame and withstand the pressure and force they are asked to endure. Also they do not walk as upright as humans because they also use their hands for walking.
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). This is an age old argument but from all the scientific research that I have seen, humans and apes both evolved from Lucy. The skeletal remains of Lucy indicate that both humans and gorillas share common skeletal structure with this ancestor
d. Provide an image of each species in this comparison. (5 pts)
Gorilla Hands Human Hands
a. Briefly describe the two different species that possess the analogous trait. (5 pts)
Fish are aquatic creatures who have an ancestor that comes from the sea while penguins have an ancestor which are fowl. They both share fins as an analogous trait which are not from a common ancestor.
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.
Both penguins and fish have fins which allow them to navigate in the water. They are similar as they both protrude from the sides of their body which gives them the ability to swim.
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)
Penguins evolved from more ancient penguins which came from Jurassic birds that could fly at one point while fish evolved from ostracoderms, small jawless prehistoric fish.
d. Provide an image of each species in this comparison. (5 pts)
Hey there,
ReplyDeleteI truly find it quite amazing how our physical structures are nearly identical to the gorillas. Its mind bottling to know that the only reason we have evolved in a different manner is for the simple fact that we have to adapt to our own habitats. Aside from those differences, it is still fascinating to hear and see all this information and in my opinion it brings up another age old question about us humans possibly being descendants of the ape family?
Good opening description of your homologous traits.
ReplyDeleteFor your second section, you do a good job of explaining why gorilla hands are the way they are, but what about human hands? Why didn't humans just keep the strength and length of their fingers, even when they stopped being arboreal? What are human hands used for? This needed to be part of your discussion as well. Don't assume, just because we are humans, that we don't need to fully explain the human animal just like any other animal.
No, Lucy is a hominid, and therefore just part of the human family tree, not an ancestor of apes in general. Since both humans and gorillas are apes, you need to go back to an archaic ape as the common ancestor, and we know from the fossil record that early apes possessed the ancestral hand structure, which was passed onto these two descendant species, with changes occurring due to different selection pressures. That's what we need to know to confirm homology.
Okay on your description and discussion of fish and bird fins. Fish have a lot of fins, so it would have been good to expand your explanation here to describe which of those fins you are comparing here. All of them? Or just the mobile pectoral fins that lie in approximately the same place as the penguin fins. Can you describe the fins of the penguin? Are they fins or actually feathered wings?
While I don't disagree with your identification of ancestry of each species, remember that the point here is to try to understand the state of the *common* ancestor and how this information on ancestry helps to confirm analogy. The common ancestor of the penguin and fish is an archaic 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? 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.
As humans evolved, we developed tools that did not require us to use our hands the way gorillas do. Our hands are used for more menial tasks not as primitively as gorillas do. This is where the separation in size and strength evolved down different paths.
DeleteBetter, but "menial"? :-) Let's think scientifically here. Humans did lose their locomotor use for their hands, and so the strength and mass were unnecessary. Evolution replaced them with dexterity and fine motor skills that allows for complex manipulation of tools and small items. Can you imagine a gorilla handling a sewing needle or doing the detailed work on a computer mother board? Those things aren't "menial". They are human activities just as stripping leaves off a branch to make a bed for the nigh and knuckle-walking is a gorilla activity. Avoid the judgment words. Straight descriptions.
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