The species I selected for this assignment are the cat and the dolphin, it might seem a little weird because you're probably thinking to yourself how in the world are these to animals related? Well, they both carry the homologous trait which means similarities between organisms based on descent from a common ancestor. The paw of a cat and the flipper of a dolphin have very much in common. They have different functions but both include the humerus, ulna and radius. All of the bones listed show that they both have a common ancestor. A cat uses its paw to climb up trees and any high area but a dolphin uses its flipper for steering itself through water along with the tail. Cats and dolphins both use these parts of their bodies to "travel" from one place to another. The front limbs on a dolphin are called flippers, the bones inside the flippers are similar to the bones in a humans arm and hand also inside the cats forearm and paw. Dolphins descendants 'Cetaceans' are from land mammals which can lead to why dolphins and cats have similar bone structures. Land mammals became adapted to aquatic life which could be why the dolphin lives in water and the cat lives on land.
Analogous Traits
The two species that I decided to compare for the analogous traits are a butterfly and an owl. As we all know both butterflies and owls have wings. Both species use their wings for survival and to fly from one place to another. Both of these species adapted to the environment of living in air which is why they developed wings which are used for flying.They have more differences than similarities, An owl has one pair of wings but a butterfly has two. A butterfly does not have any bones in its wings and an owl does. An owls wings are covered in feathers but a butterflies wings are covered in scales.
Hello Amy,
ReplyDeleteI also chose a dolphin on my assignment. I think it was very creative mixing the cat with the dolphin. I, like many other people would have thought that the dolphin was a fish. I would have guessed that a shark was a mammal, but that is not correct. Like how you articulated the function of the flipper function, where the limb is used in conjunction with the rear tail, almost as a balancing aquatic balancing system. Much like a human uses the arms and legs to balance while walking or running.
Your analogous choice and articulation was well written as well. The fact that the wings have evolved to adapt to settings is interesting. I would have thought that the butterfly wings were sobered with some type of soft fur not scales. Good use of photographs to give a visual effect.
Hi Amy,
ReplyDeleteI also chose to study the butterfly and the bird wing for the analogous trait, it is true that the only real similarity is that they use them for flying. Birds' wings have bones and ligaments while butterflies have membranes, birds have feathers and butterflies don't, etc... despite this the pressures for these organisms forced them to adapt to life in the air. Nice post! Concise and to the point.
Good discussion on your homologous trait. It can always be a little sketchy when you choose a domesticated animal for one of your organisms because they are significantly influenced by artificial selection (not natural, i.e., from the environment) but in this case, you chose a trait that developed long before humans came on the scene. Good descriptions of functional/structural differences and a good discussion on how the ancestor carried the ancestral trait.
ReplyDeleteI agree that owl and butterfly wings are analogs, but not just based upon their structural differences. Remember that appearances can be misleading and you need to look at ancestry to answer the question, not used structure to draw conclusions on ancestry.
It is difficult to go all the way back to the common ancestor or the butterfly and the owl to see if they possessed the trait, but do we need to? All we need to know is whether the trait of wings has arisen independently in at least one of these organisms. We may not know a lot about butterfly evolution (I don't, personally) but we know quite a bit about bird evolution, enough to know that wings arose in birds as they split off of reptiles. In other words, bird wings arose long after the split from butterflies, i.e., the arose independently.
Other than this final point, good post. Just make sure you understand this concept of ancestry for analogous traits.