Mark I. Vuletic

Last updated 21 March 2008

Analysis

First of all, many populations of fish are in fact continuing to evolve. One should not, however, expect them to again evolve fully into amphibians, because the niche they would be exploiting is already occupied by amphibians. D. H. Patent explains:

Many animals of today appear to be in transition between like in the water and life on land. These organisms can survive at least for limited periods of time in either environment. But we cannot say what the future holds for them. We do not know if they are "on the way" to a terrestrial existence. The chances are, in fact, that they are not really evolving away from an acquatic existence. A species cannot take over a niche that is already occcupied by another unless it is in some way better adapted to that niche. Since present land animals have been evolving for millions of years, they have become about as well adapted to land living as possible; a newcomer which is trying to "fit in" is not likely to displace them. (Patent 1977:58-59)

References

Patent DH. 1977. Evolution Goes on Every Day. New York: Holiday House.