Analogy/Homology Assignment

1A.      Humans and horses derive from a common ancestor and both species possess homologous traits such as limbs that have the same bone structure.

1B. Humans and horses are both limbed creatures.  Humans have arms and horses have legs. In humans, the arm limbs are made up of the humerus, radius, ulna, metacarpals, and phalanges.  Similarly, horses also have these components in their leg limbs.  The function of the arm trait enables humans to build, carry climb, etc..  The function of the leg trait in horses is different from that of the human arm.  A horses leg allow a horse to gallup, run, walk, pull equipment, and catapult their weight, and carry the weight of other objects.  As the two species evolved, each animal developed various uses for these traits, hence as the uses changed, the trait also changed, to form the variation in uses and appearances in the respective species we see today.

1C.  Humans are categorized under the order: primates.  Horses are grouped under the order: perissodactyla.  The commonality between horses and humans is that both orders are members of the subclass Eutheria, which are placental mammals.  Proving that the common ancestor, Eutheria, had this same homologous trait (moveable limbs) is very difficult, because the fossils that have been discovered are limited to mostly dental and skull remains.

1D. 

2A.  Bats and butterflies are both examples of analogous creatures.  They both have wings that perform the same function of flying, but both species look different and they are not derived from a common ancestor.

2B.  The wings are the analogous traits between a butterfly and a bat. The function of this trait allows both species to fly and perform aerial locomotion.  Structurally, butterfly wings lack bones and they are covered in scales. Additionally, butterflies have two pairs of wings.  In opposition to butterflies, bat wings have bones and they are covered with bare skin. Furthermore, bats only possess one pair of wings. Although the aforementioned data proves that the structure of the wings of the butterfly and the bat are significantly different, this analogous trait exhibits similarities in that both types of wings allow for aerial locomotion.

2C.  True. All organisms share some form of common ancestor, however, butterflies are categorized as insects, whereas bats are categorized as flying mammals.  There is no scientific proof or fossil records indicating that either species is closely related, therefore, wings have evolved independently in these two species. Thus the wings of both species can be considered an analogous trait.

2D.