Genetics is the study of Heredity. Heredity deals with the transmissions of characteristics from one generation to another.


Observable differences within a species are called variations. There arte two types of variations.

(a) Continuous variations. Observable differences within a species with intermediate forms are called continuous variations. E.g. height of students in a class, intelligence of students, Skin color. This is due to the result of two factors.

  1. The genes that are inherited by an individual.
  2. The effect of environment on the individual organisms.

The environmental factors are

a)         The availability and type of food.

b)         Diseases

c)         The climate – amount of sunlight, temperature, amount of water etc.

d)         The ions present in the soil

e)         Inter and intra specific competition.

(b) Discontinuous variation. Observable differences with in a species with out intermediate forms. Example. a tongue roller or a non-roller, horned cattle or hornless, blood groups, gender etc. This is due to the inheritance only and the environmental factors have no influence on it.

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