Analogy/Homology Blog Post

1.For your homologous traits provide the following information (25 pts):

a.                  Briefly describe the two different species that possess the homologous trait. (5 pts)

Two different species that possess homologous traits are whales and Homo sapiens. Whales are a species that have two fins and a tail, which allows them to live in the ocean. Homo sapiens are a species with two arms and two legs, which allows them to live on land.

b.                  Describe the homologous trait of each species, focusing on the differences in structure and function of the trait. Why do these homologous traits exhibit differences between the two species? Make sure your explanation is clear and complete. (10 pts)

A common homologous feature among whales and Homo sapiens is the whale’s fin and a person’s arm. They both possess a skeletal structure that includes an ulna, radius, carpal bones, metacarpal bones, and phalanges. Although the configuration is not quite the same, as a fin is somewhat round shaped and an arm is long with a wrist and five fingers at the end of it.

c.                  Who was (generally, not specifically) the common ancestor of these two species and how do you know that ancestor possessed this homologous trait? (5 pts)

Whales and Homo sapiens are both classified as mammals, which all possess a similar limb structure. Therefore, this particular trait was inherited form a common ancestor, which most likely differentiated over time as a result of environmental change. It is possible that whales once possessed legs as well, but eventually lost them and gained fins. People still need their legs to survive, which is why we still have them.

d.                  Provide an image of each species in this comparison. (5 pts)

 

2. For your analogous traits provide the following information (25 pts):

a.                  Briefly describe the two different species that possess the analogous trait.  (5 pts)

Two different species that have an analogous trait are turtles and snails. Snails and turtles both have an outer shell which they use as protection from their predators.

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.  (10 pts)

Turtles and snails both possess protective shells. Both species are very slow, so they utilize their shells as a type of defense against predators. Typically turtle shells are very durable, as they are made of bone, similar to a vertebra. Meanwhile, snail shells are less durable and act as the species’ only bone in the form of an exoskeleton.  

c.                  All pairs of organisms share some common ancestor if you go back far enough in time.  Did the common ancestor of these two species possess this analogous trait?  Why or whynot?  (5 pts)

Ancestors of neither turtles nor snails had a protective outer shell. Turtles are classified as reptiles and ancestral reptiles did not have shells like this. Snails came from slugs and other species without shells. Therefore, there was no shelled common ancestor that passed this trait onto either organism.

d.                     Provide an image of each species in this comparison.  (5 pts)