Reproduction in Organisms Each and every organism lives for inly a certain period after which it meets a natural death. The period between birth and natural death of an organism id called life span. Life span varies from less than one day to more than 4000 years. Life spans are3 not related to size or complexity of the organisms. Crows and parrots are of equal size. Crow has a life span of only 15 years, while parrot lives for about 140 years. Similarly, Mango tree lives for about 200 years while peepal has a life span af about 2500 years. Banyan tree spreads over a very large area but does not live beyond 500 years. The largest living plant is a shrub called It is 43000 years old. The longest life span amongst animals is that of an edible clam it is 410 years. Therefore, life span is a specific trait of each organism. it depends upon the timing of natural death. Natural death is a certainity in every individual organism. No organism is immortal. However, some single-celled organisms so not have natural death. When they grow up, they undergo binary fission. A mother cell divides into two equal daughter cells. No body part is left to die. Such organisms are immortal. Reproduction is a characterstic feature of all organisms. It is the biological process to self perpetuation or continuation of species in which the grown up individuals give rise to young ones similar to them. The adults who give rise to young ones are called parents. The young ones are called daughters or offspring The young ones grow, mature and repeat the process. There is thus a cycle of birth, growth, maturity and death. Reproduction ensures the continuity of species generation after generation Functions of Reproduction 1. Continuity of species. A species continues to live indefinitely because of the reproduction of its individuals. 2. Replacement. It replaces individuals dying due to senescence or ageing, predation and disease. 3. Population Organisation. It maintains population organisation consisting of young, adults and aged individuals.