Some fish have evolved to exploit the mouthbrooding behaviour of other species.

However, the wider world wouldn't listen to him, based upon his theory that the fish would evolve to become terrain-viable.

Remember that although it would seem impossible, some fish did evolve so as to live out of water.

"We continually ask, how can this fish have evolved so little?"

Later, about 420 million years ago, the jawed fish evolved from one of the ostracoderms.

The results show that fish evolved into a wider diversity by that time than scientists had thought.

But either way, this is not a good example, since the fish has evolved to be more fit to its environment, which includes humans.

Over time, the fish may have evolved the mating preferences that now help keep the two populations distinct.

Another fish, called Pachystomias, has evolved an even more ingenious hunting method.

The fish have evolved fairly drastic changes to their physiology to compensate.