Homologous Trait.
The tailbone of a human is analogous to the structure of the beginning of many animals' tail's, such as monkeys.
The function of the tailbone in humans is to connect ligaments, muscles, and tendons. The function of the tailbone in monkeys is to attach their tail which they use to swing from trees and to do other various activities. Some people say that the tailbone in humans is vestigial, but not entirely useless.
The common ancestor for these two could be a monkey, but when someone says that, they think of one with a tail. The ancestor could have been more of an ape, bonobo, or gorilla, but the common ancestor is extinct.
Analogous Trait.
The Analogous trait that I found is shared between a fish and a penguin which is a fin. The fins on both of these animals help them navigate their aquatic environment. The fins on the fish help it swim. Both of these animals inhibited these adaptations from the environment, rather than a common ancestor. The common ancestor of a penguin is a pheasant.
Your homologous trait comparison was one I would have not thought of. I could not imagine having a tail. Which do you think evolved first?The tail evolving to just the tailbone or tailbone to tail. Judging from this fossil, I think the tail evolved to the tailbone.
ReplyDeletehttp://www.sciencedaily.com/releases/2009/05/090519104643.htm
Known as “Ida,” the fossil is a transitional species – it shows characteristics from the very primitive non-human evolutionary line (prosimians, such as lemurs), but is more related to the human evolutionary line (anthropoids, such as monkeys, apes and humans). At 95% complete, the fossil provides the most complete understanding of the paleobiology of any Eocene primate so far discovered.
It had never occurred to me that the fins of a fish and penguin could in any way shape or form be related because when i think of a fin on a penguin i think of it more as an "arm". Interesting fact.
ReplyDeleteYes, I see how someone like you can think of a penguin's fin as more of an arm or flipper. Thanks for pointing that out.
DeleteYou did a good job explaining the structural/functional differences between humans and tailed non-human primates.
ReplyDeleteYou got into some trouble discussing ancestors.
Modern primates cannot have modern primates (like bonobos or gorillas) for ancestors. It's like saying your cousin is your ancestor. Additionally, apes (including humans) do not have tails and arose after they split from the monkey ancestral line. So humans did not arise from monkeys, but they did arise from a common ancestor with modern monkeys. Yes, these organisms possessed a tail. How does this help support the argument that these are homologous traits?
Okay on your description of your analogous traits, particularly how you demonstrated that they arose in a common aquatic environment.
Ancestry caused problems again. When you identify a common ancestor, it has to be one that is an ancestor of BOTH species, not just one. Also, the pheasant is a modern bird, so it cannot be an ancestor to penguins. However, you are very careful to clarify that both organisms "inherited" these traits because of their environment not because of a common ancestor. I think you are trying to say that these traits arose independently? This does support the claim that these traits are analogous.
A key fact that would confirm this is that birds evolved wings after they split from reptiles, long after the line leading to birds split off from fish. While the penguin's wing resembles the fin of a fish, the basic structure is a bird wing. If we know when that wing evolved, it can help us understand how the penguin wing arose independently from the fin of a fish.
It was a little difficult to find a common ancestor for both. That was the confusing part for me.
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