page_title: List of polymorphisms
section_title: Sexual dimorphism
hierarchical_section_title: List of polymorphisms / General / Sexual dimorphism
caption_attribution_description: Anas platyrhynchos Deutsch: Die Stockente ist eine Vogelart aus der Familie der Entenvögel (Anatidae). Sie ist die in Mitteleuropa bekannteste wildlebende Ente und auch die Stammform der Hausente. Möglicherweise heißt sie „Stock“-ente, da sie zuweilen auf Weiden brütet, die auf den Stock gesetzt – also zurückgeschnitten – wurden. English: A Mallard pair at Mühlthal, Straßlach-Dingharting, Germany. The Mallard is the archetypal "wild duck" and probably the best-known of all ducks, is a dabbling duck which breeds throughout the temperate areas of Europe, Asia, and North America; it is also introduced in New Zealand and Australia. Español: Ejemplares hembra y varón de ánade real (anas platyrhynchos), el arquetipo de pato salvaje y probablemente el más conocido y más reconocible de todos los patos. Su zona de cria son las areas con clima templado y subtropical de Europa, Asia, Norte América, Nueva Zelanda y Australia. Français&#160;: Deux Canards colvert, un mâle et une femelle. Le colvert est l'archétype du canard sauvage, le mieux connu et l'un des plus faciles à reconnaître. C'est un Canard de surface qui vit dans toutes les zones tempérées d'Europe, d'Amérique du nord, d'Asie, et introduit en Nouvelle Zélande et d'Australie. Русский: Самка (слева) и самец кряквы - наиболее известной из диких уток. Водоплавающая птица, широко распространенная в умеренных и субтропических поясах Северной Америки, Европы, Азии, Новой Зеландии и Австралии.
context_page_description: In biology, polymorphism is the occurrence of two or more clearly different forms or phenotypes in a population of a species. Different types of polymorphism have been identified and are listed separately.
context_section_description: Most eukaryotes  species use sexual reproduction, the division into two sexes is a dimorphism. The question of  evolution of sex from asexual reproduction has engaged the attentions of biologists such as Charles Darwin, August Weismann, Ronald Fisher, George C. Williams, John Maynard Smith and W. D. Hamilton, with varied success.
  Of the many issues involved, there is widespread agreement on the following: the advantage of sexual and hermaphroditic reproduction over asexual reproduction lies in the way recombination increases the genetic diversity of the ensuing population.ᵖ²³⁴ᶜʰ⁷
caption: A female (left) and a male (right) mallard (A. platyrhynchos). Like many other species of birds, mallards display striking sexual dimorphism.
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