dimorphism

American  

[dahy-mawr-fiz-uhm] / daɪˈmɔr fɪz əm /

noun

1. Zoology. the occurrence of two forms distinct in structure, coloration, etc., among animals of the same species.

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 British  

/ 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 Scientific  

/ 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).

---

Other Word Forms

• dimorphic
  adjective

Etymology

Origin of dimorphism

First recorded in 1825–35; dimorph + -ism

Example Sentences

Dimorphism is huge among gorillas, where the males are two or three times larger than the females.

From The Guardian • Jul. 27, 2012

Dimorphism, in females of water-beetles; in Neurothemis and Agrion.

From The Descent of Man by Darwin, Charles

This is the case with seasonal Dimorphism, the first known cases of which exhibited marked differences between the two generations, the winter and the summer brood.

From Evolution in Modern Thought by Weismann, August

His remarkable paper on Sexual Dimorphism had been translated into several languages, and a furious polemic had broken out over it.

From Tales of Men and Ghosts by Wharton, Edith

Dimorphism: a difference in form, color, etc, between individuals of the same species, characterizing two distinct types: may be seasonal, sexual or geographic.

From Explanation of Terms Used in Entomology by Smith, John. B.