Kaplan Nursing Entrance Practice Exam

What defines a population in biological terms?

1. A group of organisms of the same species living closely together

2. All organisms living in a particular ecosystem

3. The total number of species in a habitat

4. A collection of various species interbreeding

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

In biological terms, a population is defined as a group of organisms of the same species that live in close proximity to one another and have the potential to interbreed. This definition emphasizes the importance of both species designation and geographic proximity, indicating that members of a population share a common environment and can interact with each other. This grouping allows for the study of population dynamics, such as growth rates, reproduction, and ecological interactions, which are essential for understanding how species survive and adapt to their environment over time. The focus on a single species also helps in examining genetic diversity, behavior, and the effects of environmental changes specifically within that group. Other choices refer to different ecological concepts. For instance, mentioning all organisms in a particular ecosystem refers to a broader community context rather than a single species. The total number of species in a habitat pertains to biodiversity but does not capture the interspecific relationships that define a population. Lastly, a collection of various species interbreeding suggests a community level interaction rather than the concentration on a single species, which is not reflective of the definition of a population.