1. Homologus Traits
1. A) Two different species that have homologous trait is a monkey and human’s opposable thumbs.
B) Both species depend on their opposable thumbs for several tasks. Without opposable thumbs these species would be handicap and have a harder time getting around. When it comes to monkey they use their opposable thumbs to grasp thinks such as tree branches and picking up objects. As for humans, they have a more flexibility for manipulating small objects and they can move their thumbs across their hands much better and farther than any other primates.
C) One of the common ancestors to the human and ape species is the hominid species. Since the earliest hominid species diverged from the ancestor were shared with modern African apes. Five to eight million years ago there have been at least a dozen different species of these humanlike creatures.
2. A) Two species that have analogous traits would be a rhinoceros and an elephant’s horn
B) Both species have a horn like feature on their head. Reason being is that they use these horns to protect them selves from attack of other predators. The rhinoceros and elephant both have a thick layer which helps protect them from attacks as well.
C) As for a common ancestor for a rhinoceros would have to be a hyracodontidae, also known as “running rhinos” showed adaptations for speed, although they do not have a horn feature like the rhinoceros. As for the elephant, they diverged from a common ancestor of the Mammutidae, which includes species termed as mastodons. Unlike the rhinoceros ancestor, the elephant’s ancestor had a horn feature, mastodon being an example.
What a great homologous trait to use! Their thumbs look just like ours and I would imagine that they are very useful like a humans thumb. Also, the horns or the elephant and rhino are interesting also. I would never think to use that as an example. It was a very interesting comparison.
ReplyDeleteHello Santos,
ReplyDeleteI really liked the homologous trait you used. It is amazing to see how much humans have in common with monkeys, apes, chimps, and gorillas. The opposable thumb was a great trait to compare. I like how you point out that although monkeys have the trait and use it functionally, humans are the only primates that have full range and ability of their thumbs. I also really like the images you chose for the homologous species, it is funny to see how the behavior in each species mirrors each other as well, maybe there is more in common than just the one trait. As for the Rhinos and Elephants, I think that you have an interesting idea. They both share the horn-like features on their head and they both certainly have thick skin, but another post I read shows that elephant tusk are incisors, not horns. I do not know which is correct, maybe both. Just thought that was interesting.
Thanks for the post. Nice work!
Jacq~
I'm going to be a little picky on the homologous trait. When discussing homologs, we tend to focus on traits that have a common ancestral origin (which you did) but that have distinctly different functions. You do try to briefly make the case, but one problem is that you picked a very general group of primates... "monkeys". Within that category, there are creatures that have thumbs that work essentially like ours in function (baboons, for example). This turns this trait into a derived trait shared by monkeys and humans, not a homologous trait with different functions.
ReplyDeleteA more specific choice would have helped. For example, comparing human thumbs with gibbon thumbs (a lesser ape) would have showed drastically different functions. Gibbon thumbs are close to being non-existent. Human hands are for detailed manipulation. Gibbon hands are for locomotion and the thumbs are hardly used at all. Big difference in function. Does that distinction make sense? (Also, ape and monkeys diverged about 30 million years ago.)
Now your analogous trait was excellent. A great example of a trait with similar function but a drastically different ancestry and origin. One caution there is that when you speak of a common ancestor, you are talking of a common ancestor between the two species, so each species will not have their own "common ancestor", they will share one. Regardless, it is correct that these traits arose independently. Their structure is entirely different.