Parthenogenesis is the ability of the ovum to develop into a new individual without being fertilized by a male gamete, Parthenogenesis occurs in a number of worms, crustaceans & insects. It divides several times by mitosis, till it grows into a new individual.Įxamples: Many fungi such as bread mold and mushroom, Some algae and ferns.When it reaches a suitable medium for growth, it absorbs water and its coat ruptures.After the spore maturation, it liberates from the mother plant to distribute in the air.Some primitive plants reproduce by means of a single cell called spores that are modified to grow directly into a complete plant.Ī spore is formed of cytoplasm with a little amount of water, a nucleus and surrounded by a thick coat, It is a single cell that modified to grow directly into a new complete organism under suitable conditions for its growth such as in some primitive plants. Seastar (Starfish) can regenerate, if one of its arms is cut with a piece of its central disc to a full sea star within a short time, this type of sea stars forms a danger on the pearl mussels since the one sea star can devour about ten mussels daily including the pearl, therefore the breeders of those mussels in the pearl farms were collecting the sea stars, tearing them up into pieces, and then throw them back into the sea, Although they tried to get rid of them, they were unintentionally helping in their reproduction, so that they resorted to burn them.Planaria (common freshwater flatworm) is able to regenerate, even if it is cut into several transverse pieces or 2 longitudinal parts, where each part will grow into a new individual.Hydra is able to regenerate as if it is cut into several transverse pieces, where each part will grow into a new individual.Regeneration is considered as a reproduction in some organisms, as any cut part will grow into a new individual. Lower animals (regeneration for reproduction) Some crustaceans and amphibians: regeneration is limited to the compensation of the cut parts only. Higher vertebrates: regeneration never exceeds the healing of wounds, especially those located in the skin, blood vessels and muscles.
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