Final answer:
Speciation due to adaptive radiation involves the rapid diversification of a single ancestral species into multiple ecological niches.
Step-by-step explanation:
b) It involves the rapid diversification of a single ancestral species into multiple ecological niches. Adaptive radiation is a unique form of speciation characterized by the rapid and extensive diversification of a single ancestral species into various ecological niches. This phenomenon is often triggered by the availability of new habitats or ecological opportunities. Unlike slow, gradual evolutionary changes (as in option c), adaptive radiation results in the relatively quick emergence of multiple distinct species, each adapted to exploit specific environments or resources. This process showcases the adaptability of a common ancestor to different ecological challenges, leading to the evolution of diverse species, each specialized for particular ecological roles. Asexual reproduction is not a defining feature of adaptive radiation, as it can involve both sexual and asexual modes of reproduction.