Title Principles-of-Inheritance-and-Variation-min.pdf ✅

1. Principles of Inheritance and Variation Principles of Inheritance and Variation INTRODUCTION y The branch of biology that deals with the inheritance of character from parents to offspring is called as genetics. The word genetics was coined by William Bateson. y The word ‘heredity’ is taken from hereditus meaning heirship. It deals with the inheritance of similar characters from parents. y The question of how offsprings resemble their parents in some characters leads to the detailed study of the organisms at the genetic level. y Aristotle pointed out that the concept proposed by Pythagoroas was not correct. He said that only the sperms do not carry the information to the offsprings but the male and female pass on information to the offsprings. MENDEL LAW OF INHERITANCE y Gregor Johann Mendel was an Austrian Monk. He conducted many experiments with garden pea plants and is considered as the ‘Father of Genetics’. y He conducted a large number of hybridization experiments on Pea plants and arrived at some conclusions. y Initially, his work did not get recognition because of the following reasons- y He applied mathematical knowledge to biology. y He talked about certain factors that people did not believe in. y During that time scientists were more interested in the work of Darwin that they could relate with. y In 1900, his results were independently rediscovered by three biologists namely, Hugo De Vries, Carl Correns and Enrich Von Tschermak. y A few years later, W. Bateson and others confirmed Mendel’s work and found that the same laws were applied to animals also. y Mendel selected pea plant as his experimental material because- y Was easily available, flowers were easy to handle. Definition Heredity: The process by which the characters are transferred from the parents to the offspring . Rack Your Brain What is the imporatnce of a short life period for the oragnism choosen as an experimental material by a geneticist for conduction of studies on pattern of inheritance?
Principles of Inheritance and Variation 2. y Flowers of pea plants remain closed till pollination. y It showed seven pairs of contrasting characters. Previous Year’s Question How many pairs of contrasting characters in pea plants were studied by Mendel in his experiments? (1) Eight (2) Seven (3) Five (4) Six Previous Year’s Question In his classic experiments on pea plants, Mendel did not use (1) seed shape (2) flower position (3) seed colour (4) pod length Definition Allele: A pair of contrasting genes of a trait present on the same loci of a homologous chromosome is called an allele.