dimorphism

[ dahy-mawr-fiz-uhm ]

noun

1. Zoology. the occurrence of two forms distinct in structure, coloration, etc., among animals of the same species. Compare sexual dimorphism.
2. Botany. the occurrence of two different forms of flowers, leaves, etc., on the same plant or on different plants of the same species.
3. Crystallography. the property of some substances of crystallizing in two chemically identical but crystallographically distinct forms.

dimorphism

/ daɪˈmɔːfɪzəm /

noun

1. the occurrence within a plant of two distinct forms of any part, such as the leaves of some aquatic plants
2. the occurrence in an animal or plant species of two distinct types of individual
3. a property of certain substances that enables them to exist in two distinct crystalline forms

dimorphism

/ dī-môr′fĭz′əm /

1. The existence of two distinct types of individual within a species, usually differing in one or more characteristics such as coloration, size, and shape. The most familiar type of dimorphism is sexual dimorphism, as in many birds (where the male is often more brightly colored than the female), spiders (where the male is often smaller than the female), horned and tusked mammals (where horns and tusks are often present in the male but not the female), and in some species of deep-sea anglerfish (where the male is reduced to a tiny parasitic form attached for life to the much larger female). Fungi also display dimorphism. For example, the same species may exist as a small, budding yeast under some conditions, but as a mass of long hyphae under others.
2. The occurrence, among plants, of two different forms of the same basic structure, either on the same plant or among individuals of the same species. The common ivy Hedera helix produces juvenile leaves with prominent lobes under conditions of low light, but adult leaves of more rounded shape under conditions of greater light.
3. The characteristic of a chemical compound to crystallize in two different forms. Potassium feldspar, for example, can crystallize as either orthoclase (at higher temperatures) or microcline (at lower temperatures).

Derived Forms

• diˈmorphic, adjective

Word History and Origins

Origin of dimorphism¹

First recorded in 1825–35; dimorph + -ism

Example Sentences

This hormonal explanation fits well with historical shifts in human sexual size dimorphism.

From Quanta Magazine

It is perhaps owing to this dimorphism that the family is able to show a very large number of natural hybrids.

From Project Gutenberg

Only after serious study of sexual dimorphism in the animal series may one venture a few reflections on feminism.

From Project Gutenberg

Animals having both sexes, do not necessarily show sexual dimorphism.

From Project Gutenberg

The fact of both the forms presenting the same case of dimorphism is very curious.

From Project Gutenberg

Gartner found the common primrose and cowslip very difficult to cross, but he knew nothing on dimorphism.

From Project Gutenberg