Kaplan Nursing Entrance Practice Exam

What defines a population in ecological terms?

1. A group of organisms of different species

2. A group of organisms of the same species

3. A group of interbreeding plants

4. A local group of predators

The correct answer is: A group of organisms of the same species

In ecological terms, a population is defined as a group of organisms that belong to the same species and live in the same area. This definition emphasizes not only the species identity but also the spatial aspect—the individuals must be in proximity to one another to interact and potentially interbreed. This interaction is crucial because it allows for genetic exchange and influences the survival and reproductive success of the population. While the other options mention groups of organisms, they either include multiple species, which would not be considered a single population, or are too narrowly defined (e.g., interbreeding plants may represent a specific subset of a population). Hence, the definition focusing on a single species aligns with the foundational principles of population ecology, making it the most accurate choice.