[quote]Alright, here's the thing about natural selection: The fish isn't going to develop limbs and a broader body if environmental factors favor the slender, streamlined body type.[/quote]Hence, the organism will not evolve to more complicated biology.[quote]If a fish evolves to the point where it has developed primitive limbs, then environmental factors must be such that these limbs are either beneficial or make no difference.[/quote]Whether you like it or not, limbs in water WILL slow you down and MAKE THE CREATURE SUSCEPTIBLE to be preyed on. [quote]Limbs are going to make a pretty big difference, so they must have some benefit. [/quote]Not always. Have you tried swimming out to open sea?[quote]So what factors would favor limbs? It's likely that the fish population had to spend brief amounts of time on wet land or in shallow water.[/quote]Slowly or instantly? And if slowly, it would have to be heriditary, but any physical gains for any organism does NOT give the offspring the same physical capabilities. Example? If you married a world-renown weight lifter as you yourself are, your children will not inherit your strength.[quote]This could...[/quote]Now we're being hypothetical?[quote]...be to get between two very close bodies of water that had been separated by drought or some other geographical factor.[/quote]That would no longer be present because it's consistency would have to remain constant throughout the entire life of an entire organism's generation.[quote]It could also be that there was a certain predator that could not reach them in those areas, so the fish would wait in shallow or no water while the creature moved away.[/quote]For it's entire life? It's food is obviously not in the shallows; hence, the predator waits.[quote]These fish now need to be able to stay out of the water for certain periods of time without suffocating or dehydrating, and they would need to be able to propel themselves in little to no water.[/quote]Now natural selection has to occur for a malnourished organism among its species. Keep in mind that you are implying that the experience will somehow become heriditary.[quote]In this case, the squat, flat underbelly body type would have been better...[/quote]Which developed by?[quote]...as they could have remain upright while the streamlined fish would fall on their sides. Stronger fins and tails would also have been favored, because the fish would have needed to drag themselves in and out of the water, and their simple back and forth motion wouldn't have been enough. So, the limbs would have been an advantage to this particular population.[/quote]Hypothetically.