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Again, however, this is not applicable to all sexual organisms. There are numerous species which are sexual but do not have a genetic-loss problem because they do not produce males or females. Yeast, for example, are isogamous sexual organisms which have two mating types which fuse and recombine their haploid genomes. Both sexes reproduce ...
Because of the free-floating nature of larvae and subsequent mixing of juvenile halibut from throughout the Gulf of Alaska, though, only one genetic stock of halibut is known in the North Pacific. Halibut growth rates vary depending on locations and habitat conditions, but females grow faster than males.
Considered by many scientists the fastest fish in the ocean, [8] sailfish grow quickly, reaching 1.2–1.5 m (4–5 ft) in length in a single year, and feed on the surface or at middle depths on smaller pelagic forage fish and squid. Sailfish were previously estimated to reach maximum swimming speeds of 35 m/s (125 km/h), but research published ...
Most normal female fish have two ovaries. In some elasmobranchs, only the right ovary develops fully. In the primitive jawless fish, and some teleosts, there is only one ovary, formed by the fusion of the paired organs in the embryo. [2] Fish ovaries may be of three types: gymnovarian, secondary gymnovarian or cystovarian.
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]
Zangroniz said studies only use a few species of fish and don't represent the more than 30,000 fish species that exist. She added pain is measured in mammals on the grimace scale, often seen in ...
Aquaculture has been the fastest growing food sector in the world for decades, and people now eat more farmed fish than wild fish. The industry has had to grow. Demand for seafood is soaring and ...
Some plant species also exhibit dimorphism in which the females are significantly larger than the males, such as in the moss Dicranum [141] and the liverwort Sphaerocarpos. [142] There is some evidence that, in these genera, the dimorphism may be tied to a sex chromosome, [142] [143] or to chemical signalling from females. [144]