Which factor is density-independent?

Which factor is density-independent?

• A. Food
• B. Space
• C. Predation
• D. Weather

Answer: (D)

The key idea is how a factor affects a population as its numbers change. Density-independent factors influence populations regardless of how many individuals are present. Weather fits this because a storm, drought, or cold spell can cause mortality or reduce reproduction for everyone in the area, no matter how large or small the population is. In contrast, food availability, space, and predation are tied to how crowded the population is. When numbers are high, competition for food and living space increases, and predation can have a bigger impact as prey become more detectable or as predator behavior shifts with prey density. That dependence on population size is why these are density-dependent factors.

The key idea is how a factor affects a population as its numbers change. Density-independent factors influence populations regardless of how many individuals are present. Weather fits this because a storm, drought, or cold spell can cause mortality or reduce reproduction for everyone in the area, no matter how large or small the population is.

In contrast, food availability, space, and predation are tied to how crowded the population is. When numbers are high, competition for food and living space increases, and predation can have a bigger impact as prey become more detectable or as predator behavior shifts with prey density. That dependence on population size is why these are density-dependent factors.