POPULATION AGE STRUCTURE DEFINITION:
population age structure is one of the characteristics of a population that shows the summary of the number of individuals of each age in the population. Age structure is useful in understanding and predicting population growth.
For instance, if you know the age of first reproduction and reproductive strategy of a population, from the life history then you can predict future population growth patterns based on age structure data.
- If most of the individuals in the population are below the age of the first reproduction, then you can predict that in the near future, the population is likely to grow.
- However, if most of the individuals are beyond reproductive age, then you can expect the population to shrink.
- An understanding of population age structure is critically important to industries that harvest living organisms.
- Even if they can calculate maximum sustainable yield, if they don’t know the age structure of their population of interest, they might over-harvest of under-harvest.
- Ecologists use nifty graphs called age pyramids to depict the age structure of populations. Age pyramids show age groups like 0-4, 5-9, or 10-14, along the vertical axis (y-axis) and population size along the horizontal axis (x-axis).
- Each age group is broken into males and females, with a bar graph for each running horizontally to the left and to the right.
- Human age pyramids from different countries are especially interesting to examine. In industrialized countries, the age pyramids are often not pyramid-like at all, with the largest numbers of people near the middle or top of the graph.
- In developing countries, however, the vast majority of people are in the youngest age categories, with few surviving to older ages.