Final answer:
The correct answer to the process where closely related species become increasingly dissimilar is b) Divergent evolution. It is characterized by species evolving in different directions from a common ancestor and is evident in various species' adaptations to their unique environmental pressures and niches.
Step-by-step explanation:
In this process, closely related species become more dissimilar over time. The correct answer to the provided question is b) Divergent evolution.
Divergent evolution is the opposite of convergent evolution and involves closely related species becoming more different from each other. This occurs when two species evolve in different directions from a common ancestor due to differing environmental pressures or ecological niches. It's often visible in features such as the reproductive organs of flowering plants which have evolved to adapt to different pollinators in various environments. Another example is the differentiation of Darwin's finches on the Galapagos Islands.
Adaptive radiation is a form of divergent evolution where a single species gives rise to multiple species, each adapted to a different niche or environment. The Hawaiian honeycreeper is a classic example, showing how one species can radiate into several new ones.