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| Anne Hathaway going to Dark Knight Rises Set |
Both of
these images show the homologous structure of the arm and front paw. The
species are obviously a dog and a human. There is a difference in the
structure being the place of the thumb and the spread of the digits themselves.
The differences in function lies in that dogs use their front paws for
locomotion while humans use their arms with opposable thumbs to grasp things
firmly and move things around. The common ancestor between these two was likely
the splitting point of the configuration of the digits themselves. The
different assortment of the digits eventually led for an upright mammal and
finally a change in the function of the arm all together.
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| Puppy waving hello |
These two
are a honey bee and a falcon and possess an analogous structure of the wings.
The structure of the wings looks somewhat similar in shape, but the actual
makeup is quite different. This being the feathers and light bones in the
falcon and a lack of both on the bee. The function is primarily the same being
the achievement of flight. These two traits are clearly analogous because of a
similar environmental stress for flight. The different environments require a
falcon to fly in order to eat and a bee to fly in order to pollinate. These two
species do not have the genes in common for the structure of the wing.
This mechanism of requiring an adaption to allow for the better possibility of
completing the necessary tasks to survive added a pressure for flight to
be achieved. The common ancestor of birds and insects did not posses wings
because the ancestor did not have the environmental pressure of requiring
flight to better survive.
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| Honey Bee |
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| Falcon |
Our posts are remarkably similar!
ReplyDeleteI choose the human hand and the porpoise, where you choose the hand and the dog paw. However all traits stem from the same common ancestor. The paw is used more for walking, the hand used for multiple purposes and the flipper for swimming but all have similarities in the structure of their paw, flipper and hand. The differences are easily seen based upon the evolution of the creature in their environment however it can also be seen that they all came from a common ancestor.
The creatures you choose for your analogous traits were again similar, I choose the butterfly rather then the bee, however the trait of the wing is the trait that is analogous. Both the bee and the butterfly have a different structure then that of the falcon, bees and butterflies both come from the insect family and have no bones in the wing. Where as the falcon is a bird and has bones in its wings.
I enjoyed reading your blog and finding that we shared the same findings in that we used very similar answers. Good Work!
Jaqi Gibson
Jonathon,
ReplyDeleteSUCH A CUTE PUPPY! I didn't think about comparing a human hand to a puppy's paw but you make a great point and explain very well how these two are homologous traits. Also your explanation of analogous traits was exceptional as well. You clearly provided an explanation of how the structures are different but they serve the same purpose. Good job!
-Stephanie
"The common ancestor between these two was likely the splitting point of the configuration of the digits themselves."
ReplyDeleteThat's an interesting statement and a possibility. The ancestor was a tetrapod mammal of some sort, but saying that the split of ancestral lines occurred at the same time as the division of foot structure suggests that the evolutionary pressures that produced the differences also caused the split. This may not be the case, as other pressures might have caused the initial split and the differences arose later, but it is an interesting idea. Do you have a more specific idea on who the common ancestor might have been? This was not required, but I'm wondering if you came across anything.
Here's a possibility: http://www.scientificamerican.com/podcast/episode.cfm?id=4B1665EC-E7F2-99DF-332752A3D3E23B03
Good work on the analogous trait. You are correct that the common ancestor did not *have* to possess the wing structure, but it is possible that it did, though it did not pass this down to at least one of its descendents. It definitely did not pass it onto birds, but I'm not sure about about the butterfly.