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REPRODUCTION IN ORGANISMS

IMPORTANT TERMS:

·     ·         Clone: Population of genetically identical individuals.

·         Gestation Period: The time from conception to birth.

·         Life span: The period from birth to death of an organism.

·         Parthenogenesis: Development of an egg (female gamete) into a complete individual without fertilization by a sperm (male gamete). 

·         Reproduction: A biological process in which an organism gives rise to young ones (offspring) similar to itself.

·         Senescence:The period between reproductive maturity and death.

·         Syngamy:Refers to the fusion of gametes.

·         Slips:Small pieces or plantlets, which can be removed and used for propagation.

·         Scion:Part of the plant (a twig or a bud) that is grafted on the stock.

·         Stock:Part of the plant that provides support and the root system.

·         Vegetative Propagation: The process of multiplication in which portions or fragments of the plant body function as propagules and develop into new individuals.

                                                 ADDITIONAL INFORMATION:

·       Reproductive Roots:The roots which bear adventitious buds and help in multiplication                           of plants.

·         Time for Horticultural Propagation: Rainy season and spring season.

·         Sexual Reproduction in plants: First studied by Camerarius (1694).

·         Twins (i) Fraternal Twins (dizygotic or non identical twins):Two offspring that have         developed in the uterus at the same time but are the result of independent fertilization of two     ovary.(ii) Monozygotic Twins (identical twins). Two offspring developed from a single     fertilized ovum. At an early stage the zygote (fertilized ovum) separates into two independent      cells that develop into offspring of the same sex with identical genetic characteristics. (iii)       Siamese Twins (United Twins). Twins jointed in a small area. Named after Chang and Eng            born in Siam (Thailand). Their parents were Chinese. Now modern surgical techniques have         made it possible to separate Siamese infants.

·         Wilmut Clone Dolly (a sheep) the world’s first cloned mammal in 1997.

·         The desert –grassland Whiptail lizard (Cnenidophorus uniparens) an all female species.           There are no males. It reproduces by parthenogenesis.

Mr. A. KINGSLIN M.Sc, BEd, Phd,(doing)

Post Graduate Teacher in Botany

St. Mary Goretty Hr. Sec School, Manalikarai 

Kanyakumari district