BIOL 1004 Lecture Notes - Lecture 8: House Finch, Nuptial Gift, Anglerfish
8 Feb 2016
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Document Summary
Natural selection can result sexual dimorphism when the different reproductive roles of males and females necessitate different traits. Males and females mosquitoes differ in mouth parts. Females have mouth parts specialized for feeding on blood while males feed on pollen. Females feed on blood because they have greater energy and nutrients requirements than males. In many species (like angler fish) females are much larger than males (sexual size dimorphism) because larger size is advantageous for the production of more or larger eggs. This situation is often refer to as fertility selection. Natural selection can also cause sexual dimorphism when males and females specialize on different resources. In the purple throated carib, beak shape differs between males and females because they feed on different types of flowers. Most of sexual dimorphism are, however, consistent with sexual selection theory. Sexual selection: a form of natural selection in which individuals with certain inherited traits are more likely than other individuals to obtain mates.
