Search results
Results from the WOW.Com Content Network
Protogyny is the most common form of hermaphroditism in fish in nature. [30] About 75% of the 500 known sequentially hermaphroditic fish species are protogynous and often have polygynous mating systems. [31] [32] In these systems, large males use aggressive territorial defense to dominate female mating.
The term gonochorism is most often used for animal species, an estimated 95% of which are gonochoric. [17] It is very common in vertebrate species, 99% of which are gonochoric. [18] [19] Ninety-eight percent of fishes are gonochoric. [20] Mammals (including humans [21] [22]) and birds are solely gonochoric. [23] and Tardigrades are almost ...
Sexual dimorphism also occurs in hermaphroditic fish. These species are known as sequential hermaphrodites. In fish, reproductive histories often include the sex-change from female to male where there is a strong connection between growth, the sex of an individual, and the mating system within which it operates. [55]
Since then at least 50 species of unisexual vertebrate have been described, including at least 20 fish, 25 lizards, a single snake species, frogs, and salamanders. [34] As with all types of asexual reproduction, there are both costs (low genetic diversity and therefore susceptibility to adverse mutations that might occur) and benefits ...
In species that use the XY sex-determination system, parthenogenetic offspring have two X chromosomes and are female. In species that use the ZW sex-determination system the offspring genotype may be one of ZW (female), [30] [31] ZZ (male), or WW (non-viable in most species, [33] but a fertile, [dubious – discuss] viable female in a few, e.g ...
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.
This species is among the longest-living species found in freshwater, with a reported age of 60 years. They are also among the largest fish species found in freshwater, with a maximum reported length of 2.5 meters (8.2 ft) and a maximum reported weight of 159 kg (351 lb). [46] [47] [48] Australian lungfish
Fisher's principle is an evolutionary model that explains why the sex ratio of most species that produce offspring through sexual reproduction is approximately 1:1 between males and females. A. W. F. Edwards has remarked that it is "probably the most celebrated argument in evolutionary biology". [1]