Question

Write a note on

1. ‘S’ – shaped growth form
2. Factors affecting population

Answer 1

1. ‘S’ – Shaped Growth or Sigmoid growth curve:

It is also called a sigmoid curve.

It has 3 phases:
1. Early or Lag phase: There is little or no growth.
2. Middle or Log or Exponential phase: There is fast growth in the population.
3. Stationary or Zero or Plateau phase:

• The population growth is zero.
• Mortality and natality are equal.
• The population becomes equal to the environmental carrying capacity.

In S (sigmoid) form, the population increases slowly at first, then more rapidly but it soon slows down gradually as the environment resistance increases.

Factors affecting Population Growth:

• The population of any country is effected by 4 factors
  1. Natality
  2. Mortality
  3. Migration
  4. Age Distribution
• More natality in any country and less mortality increases population and the vice versa. Similarly, if human Immigration is more than migration, the population will increase and vice versa.