Population Age Distribution

Estimated time: 6 minutes

CISCE: Class 12

Definition: Age Distribution

The proportion of individuals belonging to different age groups in a population is called age distribution.

CISCE: Class 12

The arrangement or composition of a population based on different age groups is called age structure.

CISCE: Class 12

The graphical representation showing the proportion of individuals in different age groups of a population is called an age pyramid.

Maharashtra State Board: Class 12

Age distribution refers to the percentage of individuals in different age groups in a population.
An age pyramid is a graphical representation of age distribution showing three groups: pre-reproductive (0–14 years), reproductive (15–44 years), and post-reproductive (45+ years).
Population size or density (N) indicates the number of individuals in a population, but it is not always measured only by counting numbers.
In some cases, biomass (total mass of living organisms) is a more meaningful measure than number, especially when organism sizes vary.
Direct counting of population may be difficult or time-consuming, especially for very large or microscopic populations.
Relative and indirect methods like trap counts, pug marks, or fecal pellets are used to estimate population size when exact counting is not possible.