polymorphism
In genetics, the coexistence of several distinctly different types in a population (groups of animals of one species). Examples include the different blood groups in humans, different colour forms in some butterflies, and snail shell size, length, shape, colour, and stripiness.
Analysis of the human genome has revealed different kinds of polymorphisms. The simplest type are those locations, where only one base is different, known as single nucleotide polymorphisms or SNPs.
polymorphism
In mineralogy, the ability of a substance to adopt different internal structures and external forms, in response to different conditions of temperature and/or pressure. For example, diamond and graphite are both forms of the element carbon, but they have very different properties and appearance.
Silica (SiO2) also has several polymorphs, including quartz, tridymite, cristobalite, and stishovite (the latter a very high-pressure form found in meteoritic impact craters).
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