Question

When does positive density dependence typically occur?

1) When the population size is small
2) When the population size is large
3) When the population size is constant
4) When the population size is decreasing

Answer 1

Positive density dependence, or the Allee effect, often happens when population size is small, benefiting individuals through cooperation.

Step-by-step explanation:

Positive density dependence, commonly known as the Allee effect, typically occurs when the population size is small. In such conditions, individuals may benefit from cooperative behaviors like increased mate availability and improved anti-predator tactics, which can increase their average fitness. This phenomenon contrasts with negative density dependence, which generally happens closer to a population's carrying capacity and leads to decreased rates of population change due to factors such as resource competition and disease transmission.