A.) The forelimbs of a frog and Gecko's possess Homologous traits.
B.) The homologous trait that frogs and gecko's share is the forelimbs that there body inherits. The differences that these two species exhibit is that frogs are born in water and gecko's are born on land. A frog is an amphibian and a gecko is a reptile. Both species are attainable to catch their food with the long tongue's that they have.
C.) The ancestor of these species is Gerobatrachus hottoni. It is believed that the ancestor has a tail of a lizard and head of a frog.
2.) Analogous trait:
A.) Frogs and grasshoppers inherit analogous traits.
B.) These two species both relax on long legs, and both have eyes on the side of their head. Many frogs are green just like grasshoppers, and both are capable of hopping when they move from place to place.
C.) Grasshoppers originally came from a species called Eoproscopia martilli. Just like the first part the ancestor for frogs is Gerobatrachus hottini. We know that this species inherits this trait because frogs have the shape of a gerobatrachus hottini and the grasshoppers have the shape of the eoproscopia martilli.
You have a very detailed blog, and I learned about species that I didn't know. You had very good examples and It was easy to understand the material. I think you did a great job on your blog and I look forward to read you last two blogs for the class.
ReplyDeleteRachel Parker
I agree with your choice of homologous traits, with some corrections:
ReplyDeleteIt isn't an issue of where species are 'born'. It is an issue of where they evolved. Frogs have evolved in an aquatic environment and geckos in a terrestrial/arboreal environment. This is why they exhibit distinct structural differences in their forelimbs.
Second, you needed to explain what these differences actually are and why they help in the given evolutionary environment. Expand.
Homologous traits are defined not only by structural differences arising from environmental/functional differences but also by the fact that the traits arose from common descent from a common ancestor who possessed the ancestral trait. You've identified a possible ancestor, but you didn't provide the information needed to confirm that these traits are homologous. Frogs are amphibians and geckos are reptiles. Reptiles arose from amphibians, so we can confirm that the common ancestor was an archaic amphibian, regardless of specifically who that ancestor actually was. Early amphibians were tetrapods, meaning they possessed the ancestral forelimb structure and passed that onto both of these organisms. That is what we needed to know to confirm homologous status.
For your analogous trait, you have chosen two organisms but what trait are you comparing here? The trait would need to be similar in structure and function but arise independently in these organisms instead of arising from common descent. You move toward comparing the hind limb structure by mentioning "hopping" but you don't follow through and describe the structures that produce the ability to hop. This would have been a good analogous pairing, since the hindlimb structure in frogs and grasshoppers did evolve independently from each other, with it developing in frogs after they split from other amphibians. Our understanding of the evolution of the grasshopper hindlimb is not as well known, but as long as we know at least one organism has evolved the trait independently, that is all we need to know that the traits are not related genetically. Specific ancestors were not needed, just an understanding of the path of evolution of both species with relation to the trait in question.
Good images.