Analogy and Homology

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

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

Humans are unique because of their a larger and more developed brain as well as their unique bipedal locomotion that is most commonly seen in humans. Bats are one of the few mammals that is able to fly. They are also nocturnal and their bones are hollow just like other birds in the world. This weight difference allows this species to bee able to fly.

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

A bat has a greater flexible tendency as opposed to birds’ bone structures. It has many similarities to the human forearm, with the exception of its thin membrane of skin located between each finger bone. A bats wing can move just like a human hand. The bat is essentially swimming in air. Another difference between the two “hands” is the thumb sticks out of the bat’s wing as a small claw. This aids bats in climbing and suspending themselves from different structures.

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

Since the bones structure and purpose of the traits are comparable with humans and bats, the traits must have come from a common ancestor. The common ancestor between bats and humans must have been a land mammal that similar bone structure within its forearm. It is believed this ancestor came into being just under 100 million years ago.

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)

Butterflies are unique because they are one of the few insects that migrate to different geographic locations with the changing seasons. However, they are one of the many insects that have the ability to fly. Most insects have the same structure in wings. They also go through metamorphosis where they change from a caterpillar to a butterfly. Eagles have very similar bone structure to the human forearm, but their wings have evolved to allow them to survive and be considered the predators in the air. Their bones are hollow in addition to many other species of birds.

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)

Both eagles and butterflies have wings. The similarity between the two is that both organisms have adapted to life in the air and because of that, their wings have evolved. However, both types of wings have evolved independently of one another. This means that they are not closely related, so “the possession of wings” is an analogous trait.

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 why not? (5 pts)

The common ancestor did not have this analogous trait, because eagle wings developed from the evolution of the forearm. The change in forearm structure for birds came much later than the separation between insects and other species. Since the wings developed at two different time periods, a common ancestor could not have possessed the analogous trait.

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