Flourishing in spectacular numbers in lakes and ponds around the world, tiny creatures known as Daphnia play an essential role in freshwater ecology. Daphnia, a type of planktonic crustacean, are the primary consumers of ...
Ecology
7 hours ago
0
69
Rising temperatures could mean no male loggerhead turtles hatch at a key breeding ground by the end of this century, new research suggests.
Plants & Animals
Jul 11, 2019
0
1
We may take it for granted that the sex of an animal is established at birth and doesn't change.
Plants & Animals
Jul 10, 2019
1
175
Gorillas have more complex social structures than previously thought, from lifetime bonds forged between distant relations, to "social tiers" with striking parallels to traditional human societies, according to a new study.
Plants & Animals
Jul 09, 2019
3
1550
As companies trim their hierarchies and form teams of employees to manage themselves, researchers from Olin Business School at Washington University in St. Louis are sounding warning bells.
Social Sciences
Jul 09, 2019
2
0
During the mating season, male damselflies battle fiercely for control of prime territories containing resources—typically patches of floating leaves used for egg deposition in wetlands—that are key to attracting females. ...
Plants & Animals
Jul 08, 2019
1
9
A team with members from China, Singapore and the U.S. has found some of the oldest examples of cranial modification in a northeastern part of China. In their paper published in the American Journal of Physical Anthropology, ...
A team of researchers affiliated with several institutions in India has found evidence of young Asian elephants forming all-male groups as a way to survive. In their paper published in the journal Scientific Reports, the ...
Paul Mirecki found himself in the middle of an Indiana Jones-style quest involving looted antiquities.
Archaeology & Fossils
Jul 03, 2019
0
0
New research led by The University of Western Australia has shown that the social conditions that a male experiences while growing up can influence the amount of X and Y chromosome sperm that he produces as an adult.
Evolution
Jul 01, 2019
0
0
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.
This text uses material from Wikipedia, licensed under CC BY-SA
