Density-Dependent & Density-Independent Factors

​Density-Dependent & Density-Independent Factors

By Takara Leornas

Limiting factors can be density-dependent or density-independent.

Density-dependent factors

Influence a population based on its size.

The larger and denser the population, the stronger the effect. Competition for resources and the spread of disease are examples of density-dependent factors. As the population becomes more crowded, individuals must compete more for food, water, and space, and diseases can spread more quickly.

Density-independent factors

Affect a population regardless of its size or density.

Natural disasters like forest fires, floods, or hurricanes are examples. If a forest fire breaks out, it doesn’t matter whether there are 10 or 1,000 organisms in the area – the fire will cause damage based on its severity, not the population size.

Open Ended

Disease spreads faster in a packed chicken farm than in a small flock. What is the limiting factor?

Multiple Choice

Disease spreads faster in a packed chicken farm than in a small flock.

• Density-Dependent

• Density-Independent

Open Ended

A forest fire burns down trees and kills animals in its path. What is the limiting factor?

Multiple Choice

A forest fire burns down trees and kills animals in its path.

• Density-Dependent

• Density-Independent

Open Ended

There isn’t enough food, so animals must compete to survive. What is the limiting factor?

Multiple Choice

There isn’t enough food, so animals must compete to survive.

• Density-Dependent

• Density-Independent

Open Ended

A hurricane destroys a population’s habitat near the coast. What is the limiting factor?

Multiple Choice

A hurricane destroys a population’s habitat near the coast.

• Density-Dependent

• Density-Independent

Open Ended

More predators start hunting deer because the deer population is large. What is the limiting factor?

Multiple Choice

More predators start hunting deer because the deer population is large.

• Density-Dependent

• Density-Independent

Open Ended

In a crowded pond, fish compete for oxygen and food. What are the limiting factors?

Multiple Choice

In a crowded pond, fish compete for oxygen and food.

• Density-Dependent

• Density-Independent

Open Ended

A volcano erupts, covering the land with ash and killing plants and animals. What is the limiting factor?

Multiple Choice

A volcano erupts, covering the land with ash and killing plants and animals.

• Density-Dependent

• Density-Independent

Open Ended

Too many plants grow in one area, causing competition for sunlight. What is the limiting factor?

Multiple Choice

Too many plants grow in one area, causing competition for sunlight.

• Density-Dependent

• Density-Independent