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Fish ovaries may be of three types: gymnovarian, secondary gymnovarian or cystovarian. In the first type, the oocytes are released directly into the coelomic cavity and then enter the ostium, then through the oviduct and are eliminated. Secondary gymnovarian ovaries shed ova into the coelom from which they go directly into the oviduct.
There are two main reproduction methods in fish. The first method is by laying eggs and the second by live-bearing (producing their young alive). In the first method, the female fish lays eggs either on the sea floor or on the leaves of an aquatic plant. A male fish fertilizes the eggs, and both then work together to protect the eggs/babies ...
A pregnant Southern platyfish. Pregnancy has been traditionally defined as the period of time eggs are incubated in the body after the egg-sperm union. [1] Although the term often refers to placental mammals, it has also been used in the titles of many international, peer-reviewed, scientific articles on fish.
[9] [10] [11] This type of reproduction has been induced artificially in a number of animal species that naturally reproduce through sex, including fish, amphibians, and mice. [ 12 ] [ 13 ] Some species reproduce exclusively by parthenogenesis (such as the bdelloid rotifers ), while others can switch between sexual reproduction and parthenogenesis.
This method of reproduction has been found in several species of the clam genus Corbicula, [34] many plants like, Cupressus dupreziana, [50] Lomatia tasmanica, [46] [47] Pando [48] and recently in the fish Squalius alburnoides.
Asexual reproduction in starfish takes place by fission or through autotomy of arms. In fission, the central disc breaks into two pieces and each portion then regenerates the missing parts. In autotomy, an arm is shed with part of the central disc attached, which continues to live independently as a "comet", eventually growing a new set of arms.
External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. [1] It is contrasted with internal fertilization, in which sperm are introduced via insemination and then combine with an egg inside the body of a female organism.
Reproduction (or procreation or breeding) is the biological process by which new individual organisms – "offspring" – are produced from their "parent" or parents. There are two forms of reproduction: asexual and sexual .