Liver and Kidney Evolution! Please Help!

[IheartTiktaal]

I'm writing several papers for a comparative vertebrate anatomy course, in which, among other things, I will discuss the reasons for anatomical differences in the liver and kidney of various organisms.

I have the class data set for the weights of the liver and kidney of a dogfish shark, mudpuppy (necturus) and cat. (As well as their body weight to do an organ weight vs. body weight analysis)

A shark's liver aids in buoyancy by storing oil, this much is apparent to me. So that guy has a big liver... as for the others.. and kidneys... I am at a loss as to what to say about comparative organ sizes. The only data we have is weight. I'm not sure how this can speak to nephron anatomy if it does at all (for osmoregulation and the like).

Any help is greatly appreciated! Many thanks!

[WhoWee]

You might want to focus your attention on one paper (and one subject) at a time - it might be more productive.

[IheartTiktaal]

I would rather only write on one subject, indeed. However for the assignment there are 6 subjects and thus 6 papers due. Each paper is a separate entity. So in essence I am focusing on one paper, and one subject, at a time .... but still doing all of them at the same time ... stressful haha.

So, any thoughts on either livers or kidneys?

[Jack the Stri]

You could expect sharks to have comparatively smaller kidneys because they can exchange waste with the surrounding water through the skin (which is why they smell like pee).