Homologous Traits, between a Human Arm and Dolphin pectoral fin.

In comparing two different species, such as a Human and a Bottlenose dolphin, we can find homologous traits. A Bottlenose dolphin is found living in the ocean, all around the world. They are mammals who venture the sea. Humans of course we know are mammals but live there life on land, crawling and then walking.  The human and dolphin come from two different habitats, they eat different diets, and are exposed to different evolutionary hurtles. The Bottlenose dolphin and the human share the same bone structure and formation with in their extended limbs. When you look at a dolphins fin and compare it to a humans arm, we see two different looking limbs. When you examine further you can see the similarities that are homologous traits. In the chart below you can see the traits that are alike, the phalanges, carpals, ulna, and radius and humerus bone fragments exist in each limb of a human and dolphin. The bones may be smaller or shaped differently between humans and dolphins because of the types of environments each animal lives in. The function of the each limb is used to complete different task or used for different methods of survival. The dolphin’s pectoral flipper is used for steering and carving through the water to make fast turns while using their back flipper to push them forward. Dolphins also use there flipper to touch and feel other dolphins for communication purposes. Humans use their arms for many tasks, such as climbing a rock structure that may be in one’s way. We also use our arms to throw weapons that will allow us to hunt and gather food. The different functions between the flipper and arm is important, we can see how the function has morphed each bone structure in the humans and dolphins limbs. The human has skinny phalanges and are shorter in comparison to the phalanges of a dolphin. The dolphins bone structure appears to be more compact and has a shorter humerus bone, pulling the flipper closer to the body. The humerus on a human is much longer extending the reach of the limb enabling a grab function. So the dolphin flipper is much more compact compare to a humans arm, but the structures are similar and that they contain similar bone placement with in the limb. Humans and Dolphins must have shared a common ancestor millions of years ago, the two species share common traits in limb placement and development. At one time the dolphin must have moved around on land slowly adapting to the ocean life over the years.  Humans must have adapted from crawling to walking allowing more use of the arm.  Homologous traits tell us that two different species have the same traits, but utilize the function of that trait differently, to adapt to the living environment. Thus human arms and dolphins fins show a perfect example of this explanation.