Biology, asked by Kiaaaa7830, 1 month ago

tara Machhali ke Janan tantra ka varnan kijiye

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Answered by DEBOBROTABHATTACHARY
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Spawning

Starfish reproduce sexually by spawning. Spawning means that the sex cells are released into the water. Starfish gather in groups to reproduce, which increases the likelihood the sperm and eggs will find each other. Starfish have sexual organs, or gonads, in each arm. During a breeding season the males' gonads fill with sperm and the females' gonads fill with eggs. When starfish spawn, the males release sperm and the females release eggs in great numbers. Female starfish may release millions of tiny eggs into the water during a spawning session.

Egg Stage

When the eggs become fertilized they develop into zygotes. Some species of starfish brood their eggs after they're fertilized. They may sit over their eggs, or form a brooding basket in which the eggs are sheltered. The eggs may be held on the starfish's central disk or in sacs between the arms. Once the eggs hatch they are released into the open ocean to drift with the current and search for food.

Larval Stage

In the larval stage the starfish is a miniscule, jelly-like blob that floats around feeding on microscopic flora and fauna. These larva are too small to be seen with the naked eye. The starfish larva metamorphosizes through several stages until it develops into a juvenile. The larva have bilateral symmetry, but in their adult form they'll have radial symmetry. Bilateral symmetry means the left and right halves resemble each other, where as in radially symmetrical animals the limbs radiate from a single point in the center of the body.

Juvenile Stage

In the last stage of larval development the starfish abandons its free-floating planktonic lifestyle for a benthic (surface-dwelling) existence. The larva anchors itself to a surface and transforms into the juvenile stage. A juvenile starfish looks like a small version of an adult.

Asexual Reproduction

If a starfish's arm is removed along with part of the central disk (the center of the body from which the arms radiate) a whole new sea star can form from that detached piece. The amputated starfish can also regenerate a new arm to replace the lost limb.

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