Final answer:
If a lineage is distinct and stable over time, it is considered that a single lineage has evolved into a distinct new one according to the evolutionary species concept. This approach helps in distinguishing different species, especially in fossil records where breeding behaviors aren't observable.
Step-by-step explanation:
In the evolutionary species concept, if a lineage is distinct and stable over time, then 'c. a single lineage evolved into a distinct new one'. This concept is integral to the study of evolution, distinguishing different species based on unique characteristics or traits. The concept is particularly important when addressing the fossil record and dealing with phylogenetic definitions, where direct evidence of breeding behaviors cannot be observed. It is through the identification of consistent and unique traits over time that scientists can determine if the fossilized remains belong to a separate species, different from any currently known species.
Defining species and distinguishing between them is crucial for understanding evolutionary relationships, as well as monitoring evolutionary changes which can be large (such as the formation of new species) or small (variations within a population). The genetic material plays a key role in maintaining the continuity of a species by storing unique genetic messages that define and differentiate each species, ensuring their continuance across generations unless mutations occur and are passed down, leading to evolution.