Anthro 101
9/13/2012
Homologous:
Humans vs Bats -
a)
Humans and bats both possess forelimbs. Though both species are mammal, the forelimb provides a different function for each species.
b)
Structure and function of the human forelimb (hand particularly) is designed for grasping and possesses five fingers. The hand of the bat also has five fingers, but is unable to grasp. However, they have webbing in between to equip them with the ability to fly. The two display differences as a result of adaptation to different environments and speciation.
c)
The common ancestor between the two was an 80 million year old shrew-like species. Scientists have discovered this through computer analysis; reading evolution backwards and putting together a large portion of this species' genotype. http://www.nytimes.com/2004/12/07/science/07paleo.html
d)
Analogous:
Butterfly vs Bird -
a)
Butterfly wings are much smaller, much weaker and much more fragile. Bird wings are much bigger, much heavier and can carry much more weight.
b)
The wings on birds are constructed of many bones, muscles that cover them, and feathers that cover the muscle. They are simply a second set of legs, only adapted for flying. Butterfly wings don't have feathers, rather, they have scales. Each species has adapted wings to carry them to destinations through the air. Butterflies transport themselves from flower to flower and birds from tree to tree. For each this is a form of survival. Butterflies need to be close to the ground to drink fluids and close to flowers for their pollen. Whereas birds become prey if they are unable to get higher than their predators, so they rest high up in the trees.
c)
There are no common ancestors between birds and butterflies, despite having adapted wings that serve the same purpose.
d)
Very well written blog. I also did bats and humans for the homologous part. All this information is very interesting to read about. Its interesting that you found the common ancestors for humans and bats because i looked and all it said was it is yet to be determined.
ReplyDeleteTo: Sallydoll
DeleteThank you. At first I couldn't find a common ancestor either. Well in truth, the ancestor I found is 80 million years old and was only discoverable through backwards evolution. A large part of the ancestor's genome was uncovered, but still science is a long way from constructing a physical being from a genome alone.
Yes! I also could not find the common ancestor between human and a bat, merely that it was a vertebra. Nice find. Also you mentioned many interesting facts about the function of a butterfly and a bird's wings and their purposes.
ReplyDeleteTo: Phoda
DeleteThank you also. Yes, the butterfly's wings serve more functions than I mentioned above, they also serve as a means of identification among other butterfly. All of these facts can be interesting, it's even interesting to see that others have compared bats and humans just like me. What trait in particular did you compare between the two?
Great homologous trait and good logic used in determining ancestry. Here is a great site that shows the skeletal systems of human and bat forelimbs: http://askabiologist.asu.edu/human-bird-and-bat-bone-comparison
ReplyDeleteEverything has a common ancestor! Unless you buy into the idea that some species were seeded on Earth from other planets (?), then all life shares a common origin with other life. With birds and butterflies, you have to go back a billion years to the common ancestor between insects and animals, but the ancestor is there. However, you don't have to go back that far to determine whether or not this is an example of an analog. Just follow the bird (or butterfly) back in its ancestry until you find an ancestor that does NOT have wings. For birds that is in the age of reptiles. That means that birds could not have inherited wings from the common ancestor with butterflies because there is a break in the wing inheritance line.
Other than that point an ancestry, good post.
Very well Written Mark, I like how you compared the Human to a Bat showing that Bats actually have fingers, pretty interesting, very Good Post, Good Job
ReplyDelete