Homologous Trait: The Forelimb
The forelimbs of a lizard and a rabbit are examples of a homologous trait. A lizard is a reptile whereas a rabbit is a mammal, but they both share a common ancestor that also had forelimbs. A rabbit and a lizard both have forelimbs. Their forelimbs all have the same bones, the humerus, the radius, and the ulna although they are both structured differently. A rabbit’s forelimbs are located underneath its body, while lizards forelimbs are located on the sides of its body. A lizard mainly uses its forelimbs to run, climb, or cling to rocks. The rabbit’s main locomotion is hopping. Fossils of a prehistoric tetrapod called Eusthenopteron were discovered and had distinct humerus, radius, and ulna bones.
Analogous Trait: Wings
Moth wings and bird wings are an example of an analogous trait. The Moth and Bird have not evolved from a common ancestor that could fly. Instead they both developed wing structures due to selective pressures in their environments. The wings are used as a form of locomotion.
Okay on your homologous trait description. The only thing I would have liked expanded was an explanation on how the structural differences contribute to the functional differences.
ReplyDeleteYou don't need to go back to lobed finned fishes to find the common ancestor. Mammals arose from a reptilian ancestor that possessed that limb structure shared by your two species. That is all you need to know to recognize that these are homologous traits. Common ancestry with different structures and functions.
Very short on content for your analogous trait. You explanation of ancestry is actually on the right track, addressing the independent evolution of flight structures, but more explanation of the traits themselves, their similarities in structure and function (part B which was worth 10 points) was needed. That said, we really don't know the flight status of the ancestor. It might have had wings. But because we know that birds evolved wings independently during their split from reptiles, that is sufficient to identify these as analogous traits.
Good images. Just expand your explanations. Show me what you know.
I wasn't aware that rabbits and lizards had similar traits that is very interesting. Do you know which ancestor these two different species of animal shared? What environmental pressures were Moths facing? What about birds?
ReplyDeleteI had a similar post for the homologous traits but used an animal other than the lizard and it was really nice to read about a different pairing for the same trait. I liked that your post was very straight to the point and I enjoyed the analogous trait.
ReplyDeleteI also wasn't aware that rabbits and lizards are similar and I'm very glad that I read your post and I learned a little more about them! I enjoyed your blog very much and it got straight to the point and was very clear and understandable.
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