Which example illustrates a density-dependent factor affecting carrying capacity?

Which example illustrates a density-dependent factor affecting carrying capacity?

• A. Competition for water.
• B. Tornado frequency.
• C. A disease outbreak independent of population size.
• D. Seasonal droughts.

Answer: (A)

Density-dependent factors are influences whose impact grows as the population gets larger. When more individuals compete for a limited resource, like water, each organism has access to less, so birth rates can drop and death rates can rise. That means the environment’s carrying capacity effectively decreases as density increases, making competition for water a clear example of a density-dependent factor affecting how many individuals the environment can sustain. In contrast, events like tornadoes or seasonal droughts affect populations regardless of how many individuals are present, so they’re density-independent. A disease outbreak that occurs independently of population size also doesn’t scale with density, so it doesn’t illustrate a density-dependent effect on carrying capacity.

Density-dependent factors are influences whose impact grows as the population gets larger. When more individuals compete for a limited resource, like water, each organism has access to less, so birth rates can drop and death rates can rise. That means the environment’s carrying capacity effectively decreases as density increases, making competition for water a clear example of a density-dependent factor affecting how many individuals the environment can sustain.

In contrast, events like tornadoes or seasonal droughts affect populations regardless of how many individuals are present, so they’re density-independent. A disease outbreak that occurs independently of population size also doesn’t scale with density, so it doesn’t illustrate a density-dependent effect on carrying capacity.