In introductory population ecology, how is population density most commonly calculated for a defined area?

• A. Divide the area by the number of individuals (e.g., $D=\frac{A}{N}$).
• B. Multiply the number of individuals by the area they occupy (e.g., $D=N\times A$).
• C. Subtract the area from the number of individuals (e.g., $D=N-A$).
• D. Divide the number of individuals by the area they occupy (e.g., $D=\frac{N}{A}$).

Answer: (D)

Verified step by step guidance

1. Understand that population density is a measure of how many individuals of a species are found within a specific unit of area.
2. Identify the two key variables needed: the total number of individuals (N) and the area (A) they occupy.
3. Recall that population density (D) is calculated by dividing the number of individuals by the area, which gives the number of individuals per unit area.
4. Express this relationship mathematically as: \(D = \frac{N}{A}\), where \(D\) is population density, \(N\) is the number of individuals, and \(A\) is the area.
5. Use this formula to calculate population density by plugging in the values for \(N\) and \(A\) from the problem context.