Bears that mark more trees may be more successful in mating

Brown bears that are more inclined to grate and rub against trees have more offspring and more mates, according to a University of Alberta study. The results suggest there might be a fitness component to the poorly understood ...

Endangered swift parrots favor sons despite female shortage

New research from The Australian National University (ANU) shows female swift parrots can determine the sex of their offspring, and they are favoring boys over girls as they face diminished survival prospects in the wild.

Young male fruit flies make females fight each other more

Mating changes female behavior across a wide range of animals, with these changes induced by components of the male ejaculate, such as sperm and seminal fluid proteins. However, males can vary significantly in their ejaculates, ...

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Female

Female (♀) is the sex of an organism, or a part of an organism, which produces mobile ova (egg cells). The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male. A female individual cannot reproduce sexually without access to the gametes of a male (an exception is parthenogenesis). Some organisms can reproduce both sexually and asexually.

There is no single genetic mechanism behind sex differences in different species and the existence of two sexes seems to have evolved multiple times independently in different evolutionary lineages. Other than the defining difference in the type of gamete produced, differences between males and females in one lineage cannot always be predicted by differences in another. The concept is not limited to animals; egg cells are produced by chytrids, diatoms, water moulds and land plants, among others. In land plants, female and male designate not only the egg- and sperm-producing organisms and structures, but also the structures of the sporophytes that give rise to male and female plants.

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