Homologus
Traits
- A: The two species I have chosen to have homologus traits were kangaroos and koalas. The homologus trait that they share are the pouches on the their stomach in which they use to carry their babies in for further development beyond the womb.B: The pouch is the obvious similarity between the two species. However, the pouch's structure is set up differently for each species. For the koala, the pouch opens backwards and down while the kangaroo's pouch opens in front of the body horizontally. The pouches have developed differently according to each species environment. For example, the kangaroo's pouch would not work right for the koala because koalas climb trees and the way it has developed would make the offspring fall out easily. Same with the koala's pouch, with the way it's developed would make the offspring fall out easily if kangaroo's had this type of pouch when they go hopping along.C: The common ancestor of these two species is Hypsiprymnodon bartholomaii which is considered a musky rat-kangaroo. These ancestors had these pouches and have evolved over time because of the competition with placental mammals.D:
Analogous
Traits
- A: The two species I have chosen to have analogous traits were dolphins and sharks. Dolphins and sharks both live in the ocean and they definitely look like each other and it's very hard to tell them apart sometimes if you saw one swimming out in the ocean from shore. They both live in the ocean but have several analogous traits.B: Sharks and dolphins have many similarities that are analogies. For example, body shape, flippers, dorsal fins and their side fins. Their flippers help each species to move in a forward motion while their fins help the species turn and stop when they want. When it comes to the dorsal fin, they obviously both have one which we see when they're swimming in the water. These fins are necessary for marine animals because it gives them stability when swimming in the water. Each of these analogous traits have evolved independently because they are far from each others branches on the “tree”. Both of the these species experience environmental pressures that allowed them to adapt in order to survive.C: If we go far back in time, I definitely feel their common ancestor could have possessed these analogous traits. Sharks have been around for many many years and have evolved from fish while dolphins are newly evolved but have evolved from land-mammals who have “returned to the water”. Fish and mammals are nothing alike if you hear their names so how could sharks who are related to fish have a common ancestor with dolphins who are closely related to elephants and other mammals? If we go back far enough in time, we could possibly find an ancestor who has possessed these analogous traits, but for now it remains unknown.
D:
Hi Kylie!
ReplyDeleteIs it bad that I forgot that koalas have pouches until I read this? If their common ancestor was Hypsiprymnodon bartholomaii, how did the koala evolve to be what it is today? I didn't even think to pick two completely different mammals... I tried to stay in the confines! Good for you.
Actually, dolphins and sharks do have a common ancestor. It is called the Pakicetus, originally found in Pakistan. Although it was a land animal, they shared many of the same traits, such as structure of teeth.
Hey Kylie,
ReplyDeleteI really enjoyed your post. I actually really enjoyed this assignment it brought me back to grade school when we used to do reports on different animals/species. I'm not even going to lie, I really didn't know that koala's had pouches. Ooops!! Thanks for the info! It's so interesting when two different species share a common trait but have different uses for them or are structured differently due to the animals habitat. Awesome post!!
Hi kylie,
ReplyDeleteWow really cool stuff here. Honestly I had no idea Koala bears had pouches. It was cool to me to learn some new things regarding the kangaroo and the koala bear and how they share those similarities. Very insightful post here i have to admit.
The koala and kangaroo pouches has always been two of my favorite homologs, but I do wonder at the sense of an upside down pouch. The upright pouch of the kangaroo is sensible, but it has been suggested that the koalas possibly arose from digging marsupials, and an top-open pouch meant smothering the baby with dirt. The koala also apparently has a sphincter at the opening of the pouch to help prevent the baby from falling out.
ReplyDeleteGreat discussion of the shark and dolphin analogous traits. You did a good job of explaining how these traits have arisen independently even though the common ancestor not only possessed the traits in question but passed them onto the shark. Well done.