AGE DISTRIBUTION AND AGE PYRAMID

 Age distribution - Every population has individual different age groups .

Then the individual of a population is divided into 3 classes

1) Pre-reproductive

2) Reproductive

3) Post-reproductive

Age pyramid - Age pyramids are the graphics representation of different age groups found in a population with Pre-reproductive group at the base reproductive ones in the middle and the Post-reproductive groups at the top.

a) Juvenile age pyramid

Juvenile age pyramid is triangular shape.

The pyramid with a brought base has high percentage of young population due to high birth rate .

Such a pyramid which has less number of reproductive and old in dividule of population called as Juvenile.

b) Stable age pyramid

Stable age pyramid is ballet shaped .

The number of Pre-reproductive and reproductive individuals are almost equal .

Post-reproductive individuals are comparatively the population size is stable.

c) Contracting age pyramid

Contracting age pyramid is urn-shaped .

An urn-shaped pyramid has a narrow base with number of young individual because of low birth rate .

The reproductive and post-reproductive are more such a population is called dying and contracting.

The number of Post-reproductive individuals is also sizeable.