How to study Darwin’s Theory for MH-CET 2014


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How to study Darwin’s Theory for MH-CET 2014

  1. 1. How to study Darwin’s Theory for MH-CET 2014 Darwin’s theory of Natural selection and the objections raised against it Darwin’s theory of Natural selection is based on the following principles: i. Over production or enormous fertility or prodigality of production: Every living organism has a great potentiality of reproduction. Therefore, they produce many young ones but only few can survive up to maturity. Any population tends to increase in geometrical proportion causing over production of its members. ii. Struggle for existence: Organisms multiply in geometric ratio but the space and food remain constant leading to competition for survival. This competition is called struggle for existence. The struggle may be intraspecific, interspecific or environmental. iii. Variations and heredity: Variations are the differences between individuals of the same species. Variations may be harmful, neutral or useful variations, i.e. they can be favourable variations and unfavourable variations. The useful variations, are preserved and passed on to their offsprings.
  2. 2. iv. Survival of the fittest or Natural selection: The organisms having useful and favourable variations succeed in the struggle for existence. These organisms are the fittest for survival. While the organisms with unfavourable variations are unfit to survive and thus nature does not select them. This is called survival of the fittest. Since the nature selects the organisms which are provided with favourable variations hence the theory is known as the theory of Natural selection. v. Origin of new species: A new species originates by the gradual accumulation of favourable variations for a number of generations. Nature selects organisms with favourable variations which have better chance for survival. The favourable characters are transmitted to the next generation. Due to gradual changes in the organism after many generations the descendants appear to be different from their ancestors. These different forms of organisms are identified as new species. Objections to Darwin’s theory of Natural selection: The objections raised against Darwin’s theory of Natural selection are as follows: i. Darwin could not explain ‘the arrival of the fittest’. He simply insisted on survival of the fittest. ii. He did not consider the hereditary principles. iii. He did not differentiate between somatic and germinal variations. iv. This theory has no satisfactory explanation for the cause, origin and inheritance of variations. v. Darwin’s theory of Natural selection does not give any idea about the inheritance of useless variations like the vestigial organs. Keep on visiting for more study material about MH-CET 2014. - Team Ednexa