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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 ...
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.
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 ...
Sexual reproduction has many drawbacks, since it requires far more energy than asexual reproduction and diverts the organisms from other pursuits, and there is some argument about why so many species use it. George C. Williams used lottery tickets as an analogy in one explanation for the widespread use of sexual reproduction. [36]
Some perch are migratory, but only in a short and local form. They also have been observed leading a semianadromous life. Yellow perch do not accelerate quickly and are relatively poor swimmers. The fastest recorded speed for a school was 54 cm/s (12.08 mph), with individual fish swimming at less than half that speed. [4]
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]