Overweight & Obesity

Vitamin B5 activates brown fat, aids weight loss in mice

Pantothenate acid, also known as vitamin B5, stimulated the production of brown fat in both cell cultures and mice, a new study finds. The study is published ahead of print in the American Journal of Physiology-Endocrinology ...

Neuroscience

Making sense of socially enhanced aggression in the brains of mice

When male animals spend time around other males of the same species, subsequent aggressive behavior tends to be amplified—this type of priming is known as social instigation. However, the pathway in the brain that leads ...

Diseases, Conditions, Syndromes

Race-based spirometry equations may miss emphysema

A secondary data analysis of the CARDIA (Coronary Artery Risk Development In Young Adults) Lung study found that emphysema is often detectable on CT scan before spirometry findings become abnormal. The findings suggest that ...

Neuroscience

Sunlight exposure found to trigger increased eating in men

A team of researchers affiliated with several institutions in Israel, working with colleagues from Columbia University in the U.S. and the Institute for Diabetes and Obesity in Germany, has found that exposure to more sunlight ...

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Male

Male (♂) refers to the sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization. A male cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually.

Not all species share a common sex-determination system. In humans and most animals, sex is determined genetically but in other species it can be determined due to social, environmental, or other factors. The existence of two sexes seems to have been selected independently across different evolutionary lineages (see Convergent Evolution). Accordingly, sex is defined operationally across species by the type of gametes produced (ie: spermatozoa vs. ova) and differences between males and females in one lineage are not always predictive of differences in another.

Male/Female dimorphism between organisms or reproductive organs of different sexes is not limited to animals; male gametes are produced by chytrids, diatoms and land plants, among others. In land plants, female and male designate not only the female and male gamete-producing organisms and structures but also the structures of the sporophytes that give rise to male and female plants.

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