What does adaptive radiation refer to?

Adaptive radiation refers to the rapid diversification of an ancestral species into multiple forms, each adapted to different environments or ecological niches. This process often occurs when a species colonizes a new area or after a mass extinction event, where surviving species radiate out to exploit different resources.

This diversification allows these species to adapt to varying conditions and can lead to the formation of new species over time, each with specialized traits suited to their specific environments. This concept is exemplified by Darwin's finches, which evolved from a common ancestor into various species with different beak shapes adapted to their food sources.

The other options refer to different aspects of evolution. The gradual evolution of a single species focuses on slow, incremental changes and does not capture the rapid diversification aspect of adaptive radiation. The extinction of species due to competition speaks to the consequences of competitive interactions between species rather than their diversification. The development of adaptations through natural selection is a broader concept that encompasses various evolutionary processes but does not specifically address the rapid spread of forms from a single ancestor as seen in adaptive radiation.