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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.
The starfish is found on hard bottoms and under stones and seaweed where it mainly feeds on other echinoderms and on bivalve molluscs. [3] In most of its range, it undergoes sexual reproduction in the winter, while in the summer, it proliferates by asexual reproduction . [ 4 ]
Asterina stellifera has a defined annual and synchronous reproductive cycle. This cycle is affected by seawater temperature and day-length, they increase chances of fertilization by controlling gametogenesis (a process in which one cell splits to form four more cells).
Fertilization is the fusion of gametes to produce a new organism. In animals, the process involves a sperm fusing with an ovum, which eventually leads to the development of an embryo. Depending on the animal species, the process can occur within the body of the female in internal fertilization, or outside in the case of external fertilization.
Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (/ ˌ æ s t ə ˈ r ɔɪ d i ə /). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class
Fertilization of the eggs take place when sperm liberated by another starfish is drawn into the gonad through the gonoduct. The eggs are few in number and have large yolks and are retained inside the starfish which is viviparous. The brachiolaria larvae that develop inside the gonads "swim" in the fluid there and are eventually released into ...
This concentration of individuals enhances the chance of fertilization when the gametes are liberated into the sea. The larvae form part of the zooplankton and drift with the currents. After passing through several developmental stages they settle on the seabed, usually among seagrass, and undergo metamorphosis into juvenile starfish.
The starfish engages in external fertilization in which the female releases the eggs and the male releases the sperm. Fertilization occurs in the water column. Its breeding season is the summer. During this time, male and female starfish can be found extremely close or even on top of one another.