1:
a)There
isn't much I can say about humans that hasn't already been said, but I was
surprised to find out that we had something in common with bats. The bones of a
bat's front limb are remarkably similar to the bone's of a human's front limb.
Bats are described as the only "true" flying mammals, and to many
they are simply rats with wings. Which to me is a good description.
Additionally, bats are nocturnal and have small eyes which they can use
in the daylight or when it's bright outside but otherwise they use
echolocation, a process similar to radar or sonar, for hunting and
navigating.
b)Humans' front arm and hand can be used for many things.
Gripping things, high fiving, driving, and typing up this blog. A bat's wings
have evolved from their front limbs. Structure wise, a bat's upper arms
and forearm bones are pretty much the same as a humans, except smaller.
However, a bat's four fingers are enormously elongated in order to support
their wing membrane and their finger bones are very thin and do not have claws,
their thumb has a prominent hook, which helps them climb walls and trees.
c)
I'm not too positive about who our common ancestor was but I do know it was a
placenta mammal, since both bats and humans are mammals that are nourished by
placenta during development.
ANALOGOUS: BAT WINGS AND BUTTERFLY WINGS
2:
a) As mentioned above, the anatomical structure of a bat's wing is much more similar to that of a human's arm than that of a butterfly. However, both bats and butterflies have wings that allow them to fly.
b)Bats have bones in their wings and they are covered in skin. A butterfly's wings on the other hand are made of two layers that are nourished and supported by tubular veins. The veins also function in a way that helps them breath. Covering the wings are scales and hair.
c) It is believed that bats evolved from a non-flying mammal that lived mostly in trees. Similar to a squirrel, this animal would leap through the air from branch to branch. Eventually, bats gained wings. However, butterflies have been thought to have been around for so long and more than likely evolved from an insect. It is very unlikely, that bats and butterflies share an ancestor.
I like how in your homologous section you described the bats and then went into the detail of why we are so different. When I did look on Google I also did notice that we have the same structure as bats in our arms and hands. I found that pretty odd because they are completely different from us. SO I did find that interesting. I also found interesting about the butterfly wing and the bat wing they are pretty much the same I would think until you go into complete detail that they are kind of the same because they are wings, but of course with detail butterflies wings don't have bones or muscles and they aren't made from or have just skin like bats do.
ReplyDeleteGreat Post!
Good homologous trait comparison. Easy on the editorializing, however! Stick with the facts for the most part.
ReplyDeleteNo need to know the specific common ancestor. If you understand that the common ancestor was mammalian, which shared the basic forearm structure, then you have what you need to know that these structures share a common genetic background, with differences resulting for differing functions and environments. That makes the homologies.
Okay on your bat/butterfly analogy. Keep in mind that for analogies, it was the shared similarities in function and environment that were to be emphasized, not the differences.
All organisms share common ancestors if you go back far enough, but the key here is, did at least one of these organisms evolve their structure independently from that common ancestor? In this case, we aren't sure about the butterfly, but we do know that the bat evolved its wing structure independently after the rise of mammals some 65 millions years ago. That makes these structure analogous.
Great images for this post.