There are so many different species scattered across the universe that have homologous traits. Homologous traits are those that are "shared between two different species because their common ancestor possessed the trait and passed it on."(Introduction to Physical Anthropology) After looking at the many different phylogenic charts that are spread out between the internet, the modules used for the use, and in the textbook I decided to look into how Moles and Dogs are related with homologous traits. Moles are mostly known for living underground in tunnels all over Europe, Asia, and South Africa. They are small mammals with over twenty different species, most found on land but some are semi-aquatic. They are apart of the Insectivora family. Dogs are classified under Carnivora because of their special classifications that would make them applicable to be a predator. They have forward facing eyes and large front teeth called canines. Although they are classified under Carnivora they are much more omnivorous when it comes down to their actually eating habits which is quite similar to that of the Mole. The homologous trait among these two mammals is their tetrapod limbs, they both have four limbs with the same bone structure, but the limbs are differently shaped. Their limbs also carry out different functions. The main function Moles use their limbs for is to burrow down into the earth with their little claws. Dogs use their limbs to run, dig, and stabilize themselves. Both species are mammals but their main ancestors are those from the Eutheria species.
Analogous Traits
In the text "Introduction to Physical Anthropology" on page 110 in chapter five it states that analogous traits are those that are "due to a common environmental pressure that caused both species to develop a similar adaption to that stress." This mechanism is known as parallel evolution. Bats and Butterflies both have wings but are not related directly. Bats are a mostly insect eating mammal that sometimes eat small mammals, fish, birds, or reptiles that are found all over the world. They are the only mammal that can truly fly. Their wings are fingers that have been elongated significantly. A butterfly goes through a metamorphosis to produce it's wings to become a beautifully colored flying insect. There are many different species of butterflies that all vary in color and pattern on the two sets of wings they possess. The analogous trait that these two species share in common is that of wings and being able to fly. Their wings give them the ability to travel from place to place easily especially in times of threat. The common ancestor of these species did not share the trait of having wings and being able to fly. Butterflies are protostomes and bats are deuterostomes.
Bibliography
"Basic Facts About Bats." Bats. N.p., n.d. Web. 19 Jan. 2015.
"Basic Facts About Butterflies." Butterflies. N.p., n.d. Web. 19 Jan. 2015.
"Carnivora (Bears, Dogs, Cats, Seals and Allies) and Families | Skulls Unlimited International, Inc. 1-800-659-SKULL." Bears, Dogs, Cats, Seals and Allies (Carnivora): Skulls and Skeletons by Order. N.p., n.d. Web. 19 Jan. 2015.
"Evidence of Evolution: Homology Sometimes a Discussion of Evolution Needs to Consider How Evolution Does NOT Happen." BIL 160. N.p., n.d. Web. 19 Jan. 2015.
Kilgore, Lynn, Wenda Trevathan, and Russell L. Ciochon. "Chapter 5." Introduction to Physical Anthropology. By Robert Jurmain. Australia: Wadsworth, 2013. N. pag. Print."Mole." (Talpidae). N.p., n.d. Web. 19 Jan. 2015
Williams, S. B., A. M. Wilson, J. Daynes, K. Peckham, and R. C. Payne. "Functional Anatomy and Muscle Moment Arms of the Thoracic Limb of an Elite Sprinting Athlete: The Racing Greyhound (Canis Familiaris)." Journal of Anatomy. Blackwell Science Inc, 24 July 2008. Web. 19 Jan. 2015.
Interesting homologous comparison. I follow your discussion of their differences in the function of the limb, but this needed a description of the trait itself and how its structure was different due to its different function in differing environments.
ReplyDeleteOkay with your ancestry identification, but the key here is did the common ancestor possess this archaic tetrapod structure and pass it onto these two descendents? Common ancestry doesn't automatically imply that their traits are the result of common descent. Why is this important to understand in order to confirm homologous status?
"Butterflies both have wings but are not related directly."
Technically, no species is "directly" related to any other species. They are related through common ancestry.
Good description on the similarities in function as a response to similarities in environmental pressures.
As far as ancestry, the common ancestor may not have had wings, but given what we know about bats, do we really need to know that? We know that bats evolved wings independently from that common ancestor when bats split off of other mammals, relatively recently. That means that they did not inherit them from the common ancestor with butterflies. That is all we need to know to confirm that these are analogous traits.
Well sourced. Good images (and cool background on your blog).