The shape of pyramids gives the reflection of growth status of a population. Identify the growth status depicted by the given pyramid.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Expanding
An age pyramid plots the share of individuals in each age group: pre-reproductive at the bottom, reproductive in the middle and post-reproductive at the top. Its shape shows whether the population is growing, stable or declining.
Option (1) Expanding — Correct. The figure has a broad base of pre-reproductive individuals that narrows upward. Many young will enter the reproductive age, so the population grows. The book calls this shape a growing population, pyramid (a) in Figure 11.1.
Option (2) Declining — Incorrect. A declining population has a narrow base: fewer young than adults, an urn shape.
Option (3) Exploding — Incorrect. “Exploding” is not one of the three shapes of an age pyramid.
Option (4) Stable — Incorrect. A stable population has a bell shape, with the young about equal to the reproductive group.
NCERT Extract:
Population Attributes – “… 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 (Figure 11.1). For human population, the age pyramids generally show age distribution of males and females in a diagram. The shape of the pyramids reflects the growth status of the population - (a) whether it is growing, (b) stable or (c) declining.”
Figure 11.1 Representation of age pyramids for human population