Any particular advantages to fishes' tails being vertical and whales' flukes being horizontal?

TheAlphaWolf

not that I'm aware. The only reason they're different orientations is because fish and whales evolved differently. fish came from lancet-like things which moved... well like fish, and whales came from mammals. if you notice, when a wolf runs it's back moves up and down and not side to side. (has to do with the lungs) so naturally the motion just stuck. now... you may be asking why if mammals evolved from fish don't mammals move like fish right? well first of all mammals didn't evolve from fish. they evolved from reptiles. if you notice, when reptiles run their back moves from side to side... which is an inefficient way of running because they can't get enough oxygen. That's why lizards run a little and then stop... then run a little more and then stop... so since it was more ineficient, mammals began running like they run now which helps them breathe better and so they can run longer. Apr 08 05, 8:00 PM

kaylofgorons

Mental image of running lizard... It's SO CUTE! Cough, cough, ahem. Apr 08 05, 8:10 PM

TheAlphaWolf

LOL... o..k... you just posted it to show your objection didn't ya? lol I knew you would! :-D Apr 08 05, 8:27 PM

kaylofgorons

Say what? "That's why lizards run a little and then stop... then run a little more and then stop..." No, seriously. I think little lizards are some of the coolest things out there. My mom won't let me have a snake, but she's thinking about letting me have a lizard as soon as my brother "kills" his last fish. If you had left it at the first half of the sentence, I wouldn't have said anything, but adding the second part made me think of geckos. If you would like me to log an independent answer, I'll have to look it up. '@_@' I don't have time--six projects due this week. Apr 09 05, 7:38 AM

Gnomon

You say mammals didn't evolve from fish. But they did. Mammals evolved from reptiles. Reptiles evolved from amphibians. Amphibians evolved from fish. Somewhere in that chain, the side-to-side movement must have changed into an up and down movement. Apr 11 05, 6:50 AM

Baloo55th

Yes, but in between the fish and the whale there was quite a long gap, and legs. Amphibians grew legs when something mud-skippery started to need to spend more and more time out of the water - probably as the pools it lived in became further and further apart. Then after evolving into reptiles and mammals, the whale's ancestor found a good sourse of food in the sea, and lost the need for the legs. This ancestor was, it is believed, rather doggy in type and the paddling motion of the back legs would give way to the flat flukes of the whale proper, rather than to vertical tail fins like a fish. A wiggling reptile evolving into a reptilian whale might well end up with vertical flukes. Besides, in the interim between being purely land based and being purely marine (the doggy things didn't suddenly dive into the sea and grow flukes and start spouting overnight), it's a darn sight easier to manoeuvre on a beach with a flat tail. Try it with an elegant fish tail and you'll either bend it something rotten or plough the sand behind you. (The mud skipper has a very reduced tail fin for this reason.) Apr 11 05, 12:22 PM

Arpeggionist

Besides, most fish (at least those among them with backbones) spend much of their time at the same depths in the water basically. Fish do not make too many sudden vertical movement. Each species will have its niche in the water and that will be good for it through its life. Marine mammals on the other hand periodically go from breathing on the surface to diving hundreds (or even thousands) of feet to catch food. Having a horizontal fluke rather than a vertical fin provides for better mobility for a mammal and allows for better vertical movement. Apr 11 05, 1:46 PM

Baloo55th

Which could be why there is no reptilian equivalent of whales and dolphins. Apr 11 05, 2:01 PM

Arpeggionist

There are sea snakes. But that's besides the point - reptiles are cold blooded and would have to deal with changes in the water temperature at greater depths (which also explains why fish generally tend to stay at the same depth). Apr 11 05, 2:31 PM

TheAlphaWolf

and sea snakes have a vertical "fin" (flattened tail). "You say mammals didn't evolve from fish. But they did" I meant not directly. Apr 11 05, 6:33 PM