For the purposes of this course, a species is defined as:
The correct answer and explanation is:
Correct Answer:
A species is defined as a group of organisms that can interbreed and produce fertile offspring.
Explanation:
The biological definition of a species is based on reproductive isolation. Organisms are considered members of the same species if they can mate under natural conditions and produce offspring that are both viable and fertile. This definition focuses on gene flow between populations. If two populations of organisms can no longer successfully breed with each other and produce fertile offspring, they are considered separate species.
This definition helps explain patterns of evolution and biodiversity. When populations of a species become geographically or reproductively isolated from one another, they may experience different selective pressures. Over time, genetic differences accumulate due to mutations, natural selection, and genetic drift. If the divergence becomes significant enough that individuals from different populations can no longer produce fertile offspring together, speciation has occurred.
However, the biological species concept has limitations. It does not apply well to asexual organisms, such as bacteria, or to extinct organisms where reproductive behavior cannot be observed. It also struggles with cases where populations can interbreed but usually do not, due to behavioral, ecological, or geographic factors.
Despite these limitations, the interbreeding criterion remains the most commonly used and practical definition in most biological fields. It reflects the genetic cohesion within a species and the barriers to gene flow that separate different species. This definition emphasizes the importance of reproduction and heredity in maintaining the distinctiveness of a species across generations.