Analogy & Homology

For your homologous traits provide the following information:

a.       Briefly describe the two different species that possess the homologous trait.

-          The two species that represent the homologous trait are the alligator and the bat. Both species possess the same “arm” structure.

 

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.

-          Both species possess the same “arm” structure. The bat’s wing and the alligator’s front legs both have a humorous, radius, ulna, and carpals. Both of these species use their “arms” to eat and maneuver around. The differences in the traits are the following. The bat’s wing structure helps support and manipulate the bat to fly where the alligator’s assist with running and propelling itself through the water.

 

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

-          The bat and the alligator share a common ancestor that also shared the same anatomical “arm” structure. The common ancestor of the reptile and the mammal is the amniotes.

 

d.      Provide an image of each species in this comparison.

 

For your analogous traits provide the following information:

a.        Briefly describe the two different species that possess the analogous trait.

-          The two different species that possess the analogous trait are the koala bear and the squirrel. Both species inherited the ability to digest poisons.

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.

-          Over time, both the squirrel and the koala bear were able to digest poisons. The koala bear’s main source of food is the eucalyptus leaves. These leaves are poisonous to most animals. Over time, the koala bears became tree dwelling animals, and the eucalyptus leaves became their main source of food. The koala bears developed special bacteria in their stomachs that break down the toxins from the eucalyptus leaves. The squirrels as well developed the ability to eat and digest toxins for tree sourced food. They developed special saliva to help process the food that carries tannin, the toxic chemical. Acorns is a common food that carries tannin.

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?

-          The koala bear and the squirrel do not have a common ancestor that possessed this analogous trait. The ability to eat and digest the poisons were the result of a common environmental pressure that caused both species to develop a similar adaptation to that stress, parallel evolution. It indicates a genetic relationship that exists between these species.

d.      Provide an image of each species in this comparison.