Which factor is most typically density-dependent in animal populations?

Which factor is most typically density-dependent in animal populations?

• A. Weather severity
• B. Fire frequency
• C. Earthquakes
• D. Disease transmission

Answer: (D)

Population regulation hinges on factors whose impact grows with how many individuals are present versus those that don’t care about population size. The idea being tested is how disease transmission behaves with density. When animals live closer together, contact rates go up, so pathogens spread more quickly. More infections can curb growth by raising mortality or reducing the number of susceptible hosts, making disease transmission a classic density-dependent factor. In contrast, weather severity, fire, and earthquakes are external events whose effects don’t depend on how many animals are around; they strike regardless of population density. So disease transmission best fits the pattern of density dependence, explaining why it’s the correct choice.

Population regulation hinges on factors whose impact grows with how many individuals are present versus those that don’t care about population size. The idea being tested is how disease transmission behaves with density. When animals live closer together, contact rates go up, so pathogens spread more quickly. More infections can curb growth by raising mortality or reducing the number of susceptible hosts, making disease transmission a classic density-dependent factor. In contrast, weather severity, fire, and earthquakes are external events whose effects don’t depend on how many animals are around; they strike regardless of population density. So disease transmission best fits the pattern of density dependence, explaining why it’s the correct choice.