Kaplan Nursing Entrance Practice Exam

How is a species defined in biological terms?

1. A group of organisms that can adapt to different environments

2. A group of organisms that can interbreed to produce fertile offspring

3. A group of organisms living in the same habitat

4. A group of organisms with similar physical traits

The correct answer is: A group of organisms that can interbreed to produce fertile offspring

A species is defined in biological terms as a group of organisms that can interbreed to produce fertile offspring. This definition emphasizes the reproductive isolation aspect of species and highlights the ability to pass on genes to the next generation, which is crucial for the conservation of genetic traits across generations. The concept of interbreeding ensures that the members of a species share a common gene pool, which contributes to the overall genetic continuity of the species. This definition is particularly important in the context of speciation, where two populations become distinct species due to reproductive barriers that evolve over time. Other descriptions, such as a group of organisms that can adapt to different environments, while relevant to ecological principles, do not inherently define a species. Adaptation does not necessarily relate to reproductive capabilities. Similarly, a group living in the same habitat does not indicate that the members belong to the same species, as different species can coexist in the same environment. Lastly, having similar physical traits can be indicative of a species, but physical similarities alone do not confirm that these organisms can interbreed and produce viable, fertile offspring. Therefore, the emphasis on interbreeding as a criterion for species definition is what solidifies the correctness of this choice.