Chapter 5, Problem 4STP

Summary Introduction

Introduction :

A density-dependent factor is a factor that is dependent on the number of members in a population per area unit in the environment. Density-dependent factors are mainly biotic factors like disease, predation, parasites, and competition.

Answer to Problem 4STP

Correct answer :

The correct answer is option (D) food competition.

Explanation of Solution

Explanation/justification for the correct answer :

Option (D) food competition. Competition between organisms also increases when density increases. When the population increases to a size so that resources such as food or space become limited, individuals in the population must compete for available resources. So, the correct answer is option (D).

Explanation for incorrect answer :

Option (A) climate. The average weather conditions in an area, including temperature and precipitation, describe the area's climate. Climate is a density-independent factor. So, this is an incorrect option.

Option (B) weather. Weather is a density-independent factor. Any factor in the environment that does not depend on number of members in a population per unit area is a density-independent factor. So, this is an incorrect answer.

Option (D) barometric pressure. Barometric pressure is the force exerted by the atmosphere. This is also known as atmospheric pressure. It is not a density-dependent factor. So, this is an incorrect answer.