a. 1. Dog: These species are carnivorous and usually furry. They were the first domesticated animal and has been kept and used for many purposes.
2. Cat: These species are carnivorous mammal and usually furry. They are also domesticated and are being loved by many men.
b. Homologous traits are those that are similar in two different species due to their common ancestors. One homologous trait I am going to identify and analyze is tail on dogs and cats. Tails are the most posterior, or caudal terminal appendage of the vertebral column. The difference in the structure of tails start with the number of vertebrae that makes up the tail. Dogs usually have six to 23 highly mobile vertebrae while cats have maximum of 20. Although both types of tails serves a similar function such as counterbalancing. Cats and Dogs both communicate easily with their tails, but same/similar movements might mean different for both organisms. Dogs also use their tails as rudders while swimming and to spread their distinct scent to the air around them.
c. The common ancestor of these two organisms must have been a carnivorous mammal that walks on four legs. This is because researchers have been able to trace the ancestral lines of these two organisms by studying the structures, functions, and fossils of past organisms. Their common ancestor would be a mammal with a similar tail.
2. Analogous
a. 1. Penguin: These species are carnivorous and are a group of aquatic, flightless birds that are highly adapted for life in water.
2. Whale: These species vary in size and are one of the longest living mammals. Whales can be separated into many suborder such as Odontoceti and Mysticeti.
b. Analogous traits are those that are similar in two different species due to common environmental pressure, not the genes that are from their common ancestors. The analogous trait I am going to analyze between Penguins and Whales are their flippers. They have developed flippers to assist themselves in swimming under water and moving freely.
c. We can currently trace back the origins of whales to land-dwelling mammals of the artiodactyl order. As they evolved, their hind limbs became flippers and bodies became more suitable for marine environment. Penguins trace back to birds that could actually fly. They have adapted to the marine environment, and therefore changed their wings into a flappers with small feathers and gained a streamlined body. Because of these evidences, flippers of the whale and penguins are not homologous traits, but analogous traits.
Interesting post to read. I liked that you chose cats and dogs to compare. I liked learning about the vertebrae differences between the two. I would have liked to read a bit more information on their similarities. I liked your example for analogous also, I learned a lot about reading where these animals evolved from and about their ancestors. Great Post!
ReplyDeleteGreat post! For homology, maybe you should have found an actual, possible ancestor of the two organisms, whether it be extinct or alive today.
ReplyDeleteHowever, I do like how everything was covered for analogous traits. You even discussed how we can go as far back as the artiodactyls to see evolution being done.
Just a few things: there are some grammatical errors (evidences, for instance. You can say "pieces of evidence" or something). Additionally, you said to close this post,
"Because of these evidences, flippers of the whale and penguins are homologous traits, but analogous traits."
"They are homologous traits, but analogous traits" sounds a bit strange. Maybe you can re-word this?
Okay on your homologous traits. Domesticated animals are difficult for this assignment as they are the result of artificial selection instead of natural selection, but in this case, you can look at the wild versions of these organisms and still see the different functions. With regard to functions, you did seem to focus quite a bit on similarities and not as much on the functional differences that was needed for this assignment. A trait that might have been easier to do for this pairing is the difference in snout size related to the different reliance upon scent (dogs) and vision (cats).
ReplyDeleteGood discussion on their ancestry.
Interesting analogous trait. I want to highlight something here. If you have focused on the limb structure in general, at the skeletal level, this would have classified as a homologous trait, because birds and mammals inherited the common limb structure from an archaic reptilian ancestor. But because you focused on the fin shape and structure itself, those are indeed analogous traits that arose separately through parallel evolution. You did a great job of explaining this distinction in your ancestral section. Well done.
Good images.
I found it very interesting to read your blog posting as well as the other student's. I also used a whale for one of my species however I used it in mine for my homologous trait and I compared it to that of a human. I do like your comparison of the cat and dog. I had a difficult time thinking of two species to compare and this just makes me realize that there are things all around us.
ReplyDelete