In introductory population ecology, how do scientists typically calculate population density for a defined area?

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

Answer: (A)

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 or volume.
2. Identify the total number of individuals in the population, denoted as \(N\).
3. Determine the size of the area (or volume) that the population occupies, denoted as \(A\).
4. Use the formula for population density, which is the number of individuals divided by the area they occupy: \(D = \frac{N}{A}\).
5. Interpret the result as the average number of individuals per unit area, which helps ecologists understand how crowded or sparse a population is in a given habitat.