I am not "playing coy," whatever that means. It is an accumulation of knowledge from a wide variety of sources: books, journals, courses, profs, discussions with colleagues, research.
Geez! Look under Wikipedia, Brittanica, or even in Webster's dictionary:
1. allometry: "relative growth of a part in relation to an entire organism"
2. polymorphism: "the quality or state of existing in or assuming different forms: as (1): existence of a species in several forms independent of the variation of sex (2): existence of a gene in several allelic forms.
3. evolution: "a theory that the various types of animals and plants have their origin in other preexisting types and that the distinguishable differences are due to modifications [mutations] in successive generations."
A polymorphism is not a mutation, nor is it evolution. It is one of the many possible variants of the expression of a morphological phenotype that is already present within the given population's gene pool. For example, hair color, fur color, different sizes and shapes of individuals. Some polymorphs become more persistent than others because they are more advantageous for fitness, with fitness measured in units of offspring reproduced. Thus in the Arctic, many of the same species that can interbreed and reproduce viable offspring are white in color, while the same species nearer the equator may be brown or black - camouflage. These are polymorphs.
Oxford Dictionary of Biology:
1. allometry: "The growth of one part of an organism at a different rate from that of the whole organism."
2. polymorphism: "The existence of three or more distinctly different forms within a plant or animal species."
3. evolution: "The process by which new species are formed from preexisting species over a period of time."
Ask.com compiles a collection of "definitions" from a wide variety of credible sources. You can pick and choose and judge for yourself which one you feel is more scientific and appropriate for the given context, i.e., biology and genetics:
http://www.answers.com/polymorphism