Week 3: Analogy/Homology Blog Post

Week 3: Analogy/Homology Blog Post

  1. Homologus Traits
a. I have chosen human beings and gorillas as both possessing the homologous traits of having arms with hands. 

b. While the structure of human arms and gorilla arms are quite similar (two sections with a hand/palm at the end), the functions are quite opposite. Humans use arms and their adjacent hands/palms to grab, lift, and hold. Gorillas use their arms to grab, lift, hold, as well as walk while holding. The four limb walk of the gorillas allows them to maintain speed and strength which is needed for defense and climbing trees in their natural environment, while humans walk on two limbs to save energy and do not have the need for climbing trees or maintaining speed and strength while moving. 

c. Generally, the common ancestor was a gorilla/ape/monkey like creature. Humans broke off of the species and evolved while the gorillas/monkeys/apes did not.  




2. Analogous Traits

a. I have chosen the penguin and the dolphin as possessing analogous traits. While both the penguin and the dolphin have fins/flippers that serve the same function they are different structures and the animals evolved from different ancestors. 

b. Penguin fins/flippers are actually more akin to bird wings, structurally. The penguin flippers protrude form the sides of the penguin and if laid flat would give the impression that the penguin could actually fly, though they are used for swimming. Dolphin fin/flippers have the stereotypical ‘fish’ look….protruding slightly off of the body on the sides. Both of flippers, although they are structured differently, are used while swimming under water to make turns and not to propel the creatures forward. 


c. Using timetree.org, I was unable to locate a common ancestor for the penguin and the dolphin. The penguin is essentially a bird that evolved to turn their wings into flippers and steer the creature in water instead of air. The dolphin is considered a ‘whale’, and its early ancestor was (likely) a lizard that became an amphibian and eventually optimized its evolution by becoming a dolphin.   


Comments

  1. Ashley LeivasFebruary 21, 2018 at 1:13 PM

    Hi,
    Since you mentioned Gorillas use all four limbs for defense and allows them to use more strength that way it reminds me of how except using the hands on the floor. The way the body bends allows for a better charge and the force football players go in for a tackle they do the same motion would be greater . I also like your comparison of dolphins and penguins though it would have been nice to see pictures of the inside of the fins/ flippers to compare that part. Good post.

    ReplyDelete
  2. Vicious VenomFebruary 22, 2018 at 1:16 PM

    Hello PAS,

    I couldn't see any of the images you uploaded. You have to save the image and then upload through blog spot. Human beings and gorillas have so many homologus traits that are the same. You mentioned the the ancestor being a monkey like creature, i wish i could have seen a picture to try and get a better image in my head of what your talking about. I did mine on chimpanzees and humans and the ancestor i got was a Gibbon. Was your ancestor a Gibbon as well? You mentioned you were unable to find a ancestor i would suggest looking up the ancestor for a penguin and a dolphin seperatly and just analyzing from there so you could at least have something. Great post, work on those pictures!

    ReplyDelete
  3. L RodriguezFebruary 23, 2018 at 11:59 AM

    Missing required images?

    The opening prompt for both sections specifically ask for descriptions, not just identifications, of your two species. Expand and provide your readers with a better foundation of understanding for these comparisons.

    You do a good job of describing the different functions of the human and gorilla forelimb, but you don't describe the difference in structure that goes along with it (and this is where the image would have helped). How does the gorilla forelimb differ from the human forelimb and how do you connect those differences to the differences in function and the environmental pressures?

    "Generally, the common ancestor was a gorilla/ape/monkey like creature. Humans broke off of the species and evolved while the gorillas/monkeys/apes did not. "

    Okay, a couple of misconceptions. First of all, the common ancestor was an archaic ape, not a human or gorilla, and certainly not a monkey, since we are talking only about apes here. Second, humans aren't the only ones to evolve. All apes have changed since splitting from that common ancestor. Be careful not to put humans on a special evolutionary pedestal. We really aren't that unique, as I will hope you will realize over the next few weeks.

    You also don't explain how you use this information on ancestry to confirm homology. Both humans and gorillas are apes, so we know their common ancestor was an archaic apes. We also know from the fossil record that these early apes possessed the early ape forelimb structure, passing the trait onto these two descendant species, with changes occurring due to different environmental pressures. That's the information we need to confirm homology.

    Good discussion on your analogous traits.

    RE: ancestry...

    "The penguin is essentially a bird..."

    It IS a bird. :-) No "essentially" about it.

    But again, how do we use ancestry to confirm analogy? What was the common ancestor?

    Dolphins are mammals, who arose from archaic reptiles. Penguins are birds, who also arose from an archaic reptiles, so the common ancestor was an archaic reptile. We know from the fossil record that the generalized limb structure of reptiles did NOT include fins, but we also know that the fin structure in both of these species arose long after this split with the common ancestor. Dolphin fins arose after they split from terrestrial mammals and penguin fins are derived bird wings. That is what we need to know to confirm that both these traits arose independently from that common ancestor.

    ReplyDelete
  4. UnknownFebruary 23, 2018 at 10:17 PM

    Hi,

    I found your post very informative and well put together but wasn't able to view your images that you uploaded. I think you should of given a better response to the first question for the homologous trait species but you chose interesting two species for that portion, human and gorilla. I found it interesting when you talked about how humans and gorillas used their hands and palms differently. Gorillas use all four limbs to gain movement and climb while humans only use two limbs to get around. The the two species you've chosen for the analogous trait are interesting and really intrigued me. If said that there isn't a common ancestor, were you able to find anything close/recent linking the two?

    ReplyDelete

Post a Comment

Popular posts from this blog

Language

Part 1 I found Part I of the experiment to be extraordinarily challenging, though not as much so as Part II (more on that in a bit). I found the experiment difficult because it involved me not communicating! It was interesting to see the way that my partner would respond as well. For instance, because I was not communicating a response, they began to get ansy, hesitant, and almost nervous. They didn't appear to like talking without any reciprocity. I would say that they were definitely in control of the conversation, being that I was unable to communicate with them.  They initiated everything...topic choice, topic changes, questions, etc. They asked questions and I did not answer, which made them act differently. Conversation is certainly a balance of power, and they had it all. Interestingly, I felt as if I did have some power in the conversation because they were caught so off guard by my lack of communication.  If we were part of two separate cultures I would ima...
Read more

Historical Influences on Darwin

Charles Lyell, a friend and mentor of Charles Darwin, had the most influence on Darwin's work and his theory of Natural Selection. Lyell, outside of the friendship and mentorship of Darwin, argued: "that the geological processes we see today are the same as those that existed in the past." Lyell was a proponent of a theory called Uniformitarianism, where geological processes are the same over a long period of time. "Darwin, greatly influenced by Lyell, extended that principle to biology. Species, like geologic features, evolved gradually or died out gradually." The two points that were helped by Lyell's work are, "Individuals do not change, populations do" and, "in order for natural selection to occur, reproduction must occur."(PBS) The first point helps Darwin's theory by proposing that if change happens, it happens on a mass scale. The second point helps Darwin's theory by proposing that the species must continue to exist for ch...
Read more