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Heredity, , "Heredity is the passing of characters, from parents to offsprings or one, generation to next"., , Differences Between Acquired and Inherited, traits, , wSaral, Heredity, , , , , , , , , , , , Genetics is a branch of biology which, deals with the study of Heredity and, Variation., , Variations, , Importance of Variations, , 1. The great advantage of, variation to a species is, , Acquired traits, , Inherited traits, , , , Acquired traits develop due to, the effects of environmental, factor, use and disuse of organs, , Inherited traits develop due, to reshuffling of genetic, material and mutations., , that it increases the, chances ofits survival in, a changing environment., , and special (conscious) efforts., , , , , , , , The differences in the characters [or, traits] among the individuals of a, species are called Variations., , , , Acquired traits Inherited traits, , , , 2. They provide raw, material for evolution, and development of new, species., , These traits appear, throughout the lifetime, of an individual and die, with the death of that, individual., , These traits are transferred, (inherited) by the parents, to offspring. These do not, die but are passed on to the, next generation ., , The living beings show variations of, different levels in their characters (or, traits)., , Accumulation of Variation during, Sexual Reproduction, , In asexually reproducing organisms,, variation are very little only because of, , small changes created in DNA at the time, of their replication., , , , , , , , Importance of Variations, , , , , , 3. They also provides, individuality to an organism., , Acquired traits Inherited traits, , , , Example — attached or, free earlobe, curly hair,, dimple, shape of tongue, , Example — learning of dance,, music and muscular body of, a wrestler etc., , 4. They form basis of heredity., New characters are produced, in the organisms by variations., , , , , , , , , , Sexually reproducing organisms show, great variation as compared to, asexually reproducing organisms,, because of involvement of two parents., , Mendelism, Gregor Johann Mendel, , He was born on July 22 ,1822 ata Silesian, village in Austria., , Inherited Traits, , Germinal Variations

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Mendelism, , He worked as a monk at Augustinian, Monastery at Brunn city, Austria., Rediscovery of Mendelism, , Saral, Heredity, , , , , , , , , , After 16 years of Mendel's death in 1900, Phenotypic ratio, , Mendel's postulates were rediscovered., , 3 Tall: 1 Dwarf, , , , , , Carl Correns Genotypic Ratio, Erich von Tschermak 1 Pure Tall; 2 Hybrid Tall: 1 pure Dwarf, Hugo De Veries Dihybrid Cross, , Property Advantages of properties Across in which study of, , , , a. Short life cycle, in less time., , Results of experiments were obtained, , inheritance of two pairs, of contrasting traits., , , , b. Could be grown throughout, , year year,, , More experiments can be done in a, , Dihybrid Cross, , , , ¢. Choice of cross or self, fer, , , , ion his desire., , Mendel could conduct experiment as per, , Phenotypic Ratio, Phenotypic ratio in F,, , , , d. 7 pairs of allelic characters, , Large number of choice for experiments., , , , ¢. Large number of offsprings, analysis., , , , , , Good number of data for statistical, , , , , , Monohybrid Cross, It is a cross in which only one character, , is studied at a time., , In his first monohybrid cross, Mendel, crossed a pure breed tall plant and a, pure breed dwarf plant., , Generation;, Round yellow: 9, Round green: 3, Wrinkled yellow: 3, Wrinkled green 1, Dihybrid Cross, Genotypic Ratio, RRYY: 1 RryYY: 2 RRYy: 2, Rryy: 4 YY: 1) srryy 2, Rryy: 1 Rryy: 2) Rryy: 1, , Laws of Inheritance, Mendel proposed three laws:, , Law of Dominance, The Law of Segregation, Law of Independent Assortment, , Law of Dominance, , Law of dominance explains that in a, monohybrid cross between a pair of, contrasting traits, only one parental, character will be expressed in the F1, generation., , The Law of Segregation, , In a monohybrid cross, both the alleles, are expressed in the F2 generation, without any blending., , Thus, the law of segregation is based on, the fact that each gamete contains only, one allele from the original gene., , Law of Independent Assortment, , The Law of Independent Assortment, states that during a dihybrid cross, (crossing of two pairs of traits), an, assortment of each pair of traits is, independent of the other.