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Fisheries-induced evolution differs from the Darwinian evolution model by virtue of the direct human factor. [2] For FIE, fishing enforces a greater selection pressure for traits, often through sheer effort and catch numbers, which can disparage natural selection pressures such as predator-prey interactions and environmental influences.
Nuptial tubercles or breeding tubercles (also called pearl organs or nuptial efflorescence) are noticeable skin roughness or horny nodules that form on male fish during breeding. They are made of keratin, the same material as hair, hooves, and fingernails.
Ovuliparity means the female lays unfertilised eggs (ova), which must then be externally fertilised. [10] Examples of ovuliparous fish include salmon, goldfish, cichlids, tuna and eels. In the majority of these species, fertilisation takes place outside the mother's body, with the male and female fish shedding their gametes into the surrounding ...
The synchronous spawning of many species of coral in marine reefs means that inter-species hybridization can take place as the gametes of hundreds of individuals of tens of species are liberated into the same water at the same time. Approximately a third of all the possible crosses between species are compatible, in the sense that the gametes ...
Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together.
In fish breeding, those parents frequently are two closely related fish species, while in plant and animal breeding, the parents often are two inbred lines. Gregor Mendel focused on patterns of inheritance and the genetic basis for variation .
The first fossilized evidence of sexual reproduction in eukaryotes is from the Stenian period, about 1.05 billion years old. [19] [20]Biologists studying evolution propose several explanations for the development of sexual reproduction and its maintenance.
Three-spined stickleback fish have been a frequently studied species in ecological speciation.. Ecological speciation is a form of speciation arising from reproductive isolation that occurs due to an ecological factor that reduces or eliminates gene flow between two populations of a species.