Final answer:
Stage 4 of the age structure diagrams likely represents a declining population with lower birth rates and a higher proportion of older individuals, suggesting a population decrease over time.
Step-by-step explanation:
The age structure diagrams for rapidly growing, slow growing, and stable populations represent stages 1 through 3. When considering what type of population change stage 4 represents, we refer to the descriptions provided for each stage. In stage 1, characterized by rapid growth, the diagram narrows to a point, suggesting a high number of births and a quick decrease in the number of individuals with age. Stage 2 shows slow growth, where the decrease in the number of individuals is steadier across ages. Stage 3 is for stable populations, where the number of individuals per age group decreases gradually and then increases among older populations.
Comparing stage 4 to stage 3, we would be looking to identify a shift in population growth patterns. For a shift from stage 3 to stage 4, the changes in population growth would likely include a decrease in birth rates and an overall aging population. This can lead to a demographic that consists of a higher proportion of older individuals compared to younger ones, indicating a declining population structure. Thus, stage 4 could represent a population that begins to diminish over time, often referred to as decline or contraction.