In population ecology, what is the correct formula for population density (D) when N is the number of individuals and A is the area sampled?

• A. $D=N+A$
• B. $D=\frac{A}{N}$
• C. $D=\frac{N}{A}$
• D. $D=N\times A$

Answer: (C)

Verified step by step guidance

1. Understand that population density (D) measures how many individuals (N) are found per unit area (A). It quantifies how crowded or sparse a population is within a given space.
2. Recall that to find density, you divide the total number of individuals by the total area they occupy. This gives a value representing individuals per unit area.
3. Write the formula for population density as a fraction where the numerator is the number of individuals (N) and the denominator is the area sampled (A):
4. \[D = \frac{N}{A}\]
5. Note that addition (N + A) or multiplication (N \times A) do not represent density because they do not relate individuals to area in a meaningful way.
6. Therefore, the correct formula for population density is the ratio of individuals to area, which is \(D = \frac{N}{A}\).