1. Homologous Trait: Blow holes
- Bottle nosed dolphins and blue whales are both water-dwelling mammals. Dolphins generally weigh 440 to 600 pounds while blue whales can be up to 150 tons. Dolphins eat fish, squid, and crustaceans such as shrimp. Blue whales eat mostly krill.
- These two species of Cetacea possess blowholes
- The homologous traits were inherited from a common archaeocete ancestor, which is referred to a, put simply is a primitive toothed whale.
- Dolphins are slick skinned mammals who possess blow holes, like whales. Fish are a scaled, gilled, vertebrates.
- The common trait between these particular water-dwelling vertebrates and mammals is that they both have fins and therefore are hydrodynamic. Both propel themselves through the water with their back tail and use their front and dorsal fins to maneuver.
- The common ancestor for fish and dolphins - and for all Cetacea for that matter - is though to actually be a terrestrial animal related to even toed ungulates. Their common ancestor did not share the trait because they were land dwelling animals.
I also wrote about the same analogous trait. It was interesting to learn that dolphins are not like fish, but they still have some common traits. I learned a lot from doing this assignment. I always thought whales were the only ocean mammals :)
ReplyDeleteNice work, however, I cannot see your pictures. I don't know if anyone else is having the same problem.
I wrote about the same thing for question 2! I'm glad that we found the same common ancestor for fish and dolphins!! I felt so silly putting that land animal, but I'm happy to see someone else actually found the same information in their research. I used the different uses of fins to do my comparison as well.
ReplyDeleteI was confused at first for section 2, thinking you were still talking about dolphins and whales, and then I reread the fish part! I find it interesting that dolphins could have developed fins as an environmental factor (as they are mammals) but the fish were always getting oxygen from the water?
ReplyDeleteGood choice on traits. The parallel evolution of fins is an excellent example of analogs.
ReplyDeleteA couple of points:
How do the blowholes of the dolphins and whales differ? They arise from a common ancestor but what differences have arisen since that ancestral divide? And why do these differences exist?
Unfortunately, your images didn't come through. They needed to be added in by saving the images you want to your computer and using the "add image" function in Blogger... it's the little picture icon when you are writing your post. The "Blogger Help" page has a help guide for that.
One additional point... to find the common ancestor between the fish and the dolphin you have to go all the way back to the common ancestor between fish and mammals. That's a fish!
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