Question

define heredity explain the mechanism of hereditary changes

Answer 1

Heredity (like begins like) is the study of transmission of characters from parents to offspring or from one generation to the another or next generation.
The mechanism of Heredity when it changes is when the organism has a number of traits having alternate forms represented by particulate entities or genes. The alternate forms may remain hidden for one or few generations to reappear in unchanged state making the mechanism of Heredity change in a certain amount of time as the unhidden form of the trait appears more often than its alternate one.

Answer 2

Explanation:

Heredity is the transfer of genetic characters or traits from parents to their offsprings.

The traits that are transferred to the progeny are known as inherited traits.

Example eye colour, ear lobe structure, blood group.

Heredity includes not only physical but also physio­logical qualities. These qualities may be either expressed (if the trait is dominant) or they may be latent in the offspring (if the trait is recessive).

The mechanism of heredity involves:

Mating: Fusion of the male germ cell spermatozoa with the female ovum (tranfer of gametes and their fusion)

Growth: Repeated mitotic division of the zygote (fertilised egg).

Chromosomes: Both the male and female gametes contain nucleus which further contains the chromosomes. Both of them have 24 chromosomes each. (Therefore, called haploid cells)

Gene: Chromosomes further contain smaller structures that are called genes. Now these genes are the structures that get passed on. Different genes are responsible for different characters. For example, there are genes that determine eye colour, genes that determine your blood group etc. Genes get passed onto the progeny from both the mother and father. Depending on the dominance of the gene, that particular character would be expressed in the progeny.

Chance factor: Even though each parent passes on 24 pairs of chromosomes to the progeny, the progeny doesn't have 48 pairs of chromosomes on fertilization. Due to reduction divison (meiosis) there are 24 pairs of chromosomes only. Which 24 pairs will be selected is a matter of chance and is not predetermined.

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