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PARTHENOGENESIS
Reproduction in organisms are of two types ,sexual and asexual reproduction.In sexual reproduction both male and female gamete is involved.In asexual reproduction offspring are produced without the involvement of gametes. Asexual reproduction includes fission, sporulation ,budding and parthenogenesis.Parthenogenesis is not strictly asexual reproduction as there is involvement of female gamete.

Parthenogenesis is the process of production of an embryo from a female gamete without any involvement of male gamete.Parthenogenesis are of two types natural parthenogenesis and artificial parthenogenesis.

Natural parthenogenesis
Parthenogenetic development of the egg under natural condition is called as natural parthenogenesis.For example in Aphids,Daphnia,rotifers,nematodes and other invertebrates as well as in plants.

Artificial parthenogenesis
Parthenogenesis which involves experimentally induced development of eggs by various physical and chemical agents is called artificial parthenogenesis.Variety of agents can induce the development of egg,among the chemical agents neutral salts like potassium chloride ,weak acids and bases are used.In physical agents increase in osmotic pressure,electrical stimuli and mechanical stimuli such as shaking the egg and puncturing it with fine needle.

Significance of parthenogenesis
In many aspects parthenogenesis has advantage over sexual reproduction.The significance of parthenogenesis are:
 * 1) Control of the sex ratio: In case of honey bees, queen controls fertilization and thus control the sex ratio.Fertilized egg develops into diploid female ( queen or workers),while unfertilized eggs develop into parthenotes(males).In a hive there are nearly 20,000 to 80,000 workers (diploid sterile females).Drones (haploid sterile males).Since only one queen is to be fertilized the population is reduced.
 * 2) Rapid breeding: In Aphids,female reproduce in summer by diploid parthenogenesis. Several generation of females are formed.The parthenogenesis enables rapid increase in number of females in a season where vegetation is abundant.Also ,the delay resulting from the time spent in finding a mate is not required.
 * 3) Variation:In parthenogenesis,there is no chances of genetic recombination.these species will be well adapted to survive in particular environment.But any change in environment will adversely effect on the species.Thus it is desirable to introduce variation in a population to counteract the effects of change in environment.