The age distribution plotted for the population is known as the 'Age pyramid'. Select the three types of age pyramids based on the shape and age groups:
(A) Expanding
(B) Inverted
(C) Stable
(D) Declining
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (C) and (D) only
A population at any given time is composed of individuals of different ages. If the age distribution (per cent individuals of a given age or age group) is plotted for the population, the resulting structure is called an age pyramid.
The shapes of age pyramids can be classified as follows:
- Triangular-shaped age pyramids indicate a high number of pre-reproductive individuals, a moderate number of reproductive individuals, and even fewer post-reproductive individuals. This type of population is anticipated to grow or expand.
- Bell-shaped age pyramids occur when pre-reproductive and reproductive individuals are nearly equal in numbers or percentages, with relatively fewer post-reproductive individuals. This population is expected to remain stable.
- Urn-shaped age pyramids exhibit low numbers or percentages of pre-reproductive individuals, a maximum number of individuals in the reproductive age group, and a small number of individuals in the post-reproductive age group. Such a population is considered to decline.
