Heredity

Have you ever pondered over what heredity is? Heredity or nature is an inherited quality or tendency. It covers all those factors that were present in the individual when he began life, not at birth at the time of conception about nine months before birth (Woodworth).

Floyd L. Ruch considers heredity as the totality of biologically transmitted factors that influence the structure of the body.
In the words of Peterson, ”Heredity may be defined as what an individual gets from his ancestral stock through his parents.”

Douglas and Holland state, “ Heredity consists of all the structure, physical characteristics, functions or capacities derived from parents and other ancestry or species.”

Theories of Heredity
In order to further understand the concepts of heredity, let us go through some of the important viewpoints or theories.

Wiseman’s Theory: Weismann believed that the plasma is transmitted from one generation to another and this germ plasma has continuity, and therefore his theory was known as Theory of Continuity of Germless. He explained that the human body grows from one cell by the process of cell division and the parents are taken to be the trustees of germless rather than the producers of the child.

Mendel’s View: Gregory Mendel (1886) published the results of his continuous painstaking observation of cross-breeding of plants. He discovered the laws of inheritance in hybrid peas growing in the garden of an Austrian monastery. The Mendelian law of inheritance may be summarized as:” If a man who is homozygous for blue eyes marries a woman homozygous for the brown eyes the children of this couple will have only brown eyes”.

Darwin’s theory of Natural Selection: According to this theory evolution of life takes place by natural selection of variations, produced by mutations. Darwin recognizes both slight and salutatory variations in the process.
This theory is based on three assumptions
Environment causes a struggle of life and survival of the fittest
As result variations occur which are transmitted to further generations, and
Thus evolution takes place by way of natural selection