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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 ...
Gonochoristic Fish In gonochoristic fish, the sex can be determined genetically, environmentally or by a combination of both. In fish, primary sexual fate can be susceptible to alteration by hormones exposure and multiple environmental factors, such as population density, water pH, or temperature.
The first principle of population dynamics is widely regarded as the exponential law of Malthus, as modelled by the Malthusian growth model.The early period was dominated by demographic studies such as the work of Benjamin Gompertz and Pierre François Verhulst in the early 19th century, who refined and adjusted the Malthusian demographic model.
Polygyny is where one male mates with several females in a breeding season (e.g., lions, deer, some primates, and many systems where there is an alpha male). [1] A common example of polyandrous mating can be found in the field cricket ( Gryllus bimaculatus ) of the insect order Orthoptera (containing crickets, grasshoppers, and groundhoppers).
This suggests cooperative breeding evolved from noncooperative breeding monotocy to cooperative breeding polytocy. [1] Today, there is growing support for the theory that cooperative breeding evolved by means of some form of mutualism or reciprocity. Mutualism is a form of symbiosis that is beneficial to both involved organisms.
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.
In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms for the purposes of sexual reproduction. Fertilization is the fusion of two gametes . [ 1 ] Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization . [ 2 ]
Reproductive synchrony is a term used in evolutionary biology and behavioral ecology. Reproductive synchrony—sometimes termed "ovulatory synchrony"—may manifest itself as "breeding seasonality". Where females undergo regular menstruation, "menstrual synchrony" is another possible term. Figure a. Females competing for good genes should avoid ...