Final answer:
The term used to describe the process when a species occupies more than one niche, leading to divergence and speciation, is adaptive radiation.
Step-by-step explanation:
When a species begins to occupy more than one niche, and divergence and speciation occur as a result, the term used to describe this process is adaptive radiation. Adaptive radiation is the evolutionary process by which a single species evolves into many new species to fill available niches. This process often occurs when a population of a species disperses throughout an area and each subgroup finds a distinct niche or isolated habitat, leading to multiple speciation events that originate from a single point. A classic example is the Hawaiian honeycreeper, which shows how from a founder species, numerous species have evolved to adapt to different environmental conditions in geographically isolated islands.