AP Biology Flashcards: Effect of Density on Populations
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 10 cards to help you master important concepts.
What are the two categories of factors that impose limits on population growth?
Density-dependent and density-independent factors are the two categories of factors that impose limits on population growth.
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What are the two categories of factors that impose limits on population growth?
Density-dependent and density-independent factors are the two categories of factors that impose limits on population growth.
What is Carrying Capacity (K)?
Carrying capacity (K) is the maximum population size an ecosystem's resources can sustainably support.
What type of growth model is observed as a population approaches its carrying capacity?
A logistic growth model is observed as limiting factors, such as resource scarcity, cause the population's growth rate to slow as it approaches carrying capacity.
How does resource availability determine a population's density?
The amount of available resources in an environment sets the carrying capacity, which is the maximum population density that can be sustained over time.
If a fish population in a pond grows until it reaches the pond's carrying capacity, what factors will prevent it from growing further?
Density-dependent factors (like limited food and space) and density-independent factors will impose limits on growth, preventing it from exceeding the carrying capacity.
A small island can only provide enough food for 1,000 birds. What does this number represent for the bird population?
This number represents the carrying capacity (K) of the island's ecosystem for that specific bird population.
How does population density affect resource availability?
As the density of a population increases, the availability of resources per individual decreases, which in turn can limit further population growth.
Explain the dual relationship between population density and resource availability.
Resource availability determines the potential density of a population, while the actual density of the population affects the rate at which those resources are consumed.
Define the logistic growth model.
The logistic growth model describes how a population's growth is limited by density-dependent and density-independent factors as it nears the environment's carrying capacity.
How is carrying capacity (K) related to the logistic growth model?
Carrying capacity (K) is the plateau, or maximum population size, that a population approaches in the logistic growth model.