Which term refers to a characteristic that varies with population density?

• A. Density dependent
• B. Density independent
• C. Population growth
• D. Carrying capacity

Answer: (A)

In population biology, a characteristic that changes in response to how crowded a population is is described as density-dependent. When a population becomes more dense, competition for limited resources increases, survival and reproduction can be harder, and diseases spread more easily. These effects alter birth and death rates in a way that depends on how many individuals are present, which is why this trait is labeled density-dependent.

This is different from density-independent factors, which affect the population regardless of its size—things like a severe storm or a drought that hit the area no matter how many organisms are there. Carrying capacity is the environment’s maximum population size it can sustain over time, not a trait that varies with density itself, though the population’s approach to that limit is governed by density-dependent processes. Population growth describes the change in population size, not a property that varies with density.