Adaptive radiation refers to the evolutionary process where a single ancestral species gives rise to multiple new species, each adapted to a specific ecological niche or habitat. This process usually occurs when the ancestral species enters a new, vacant habitat or when there are significant changes in the environment that create new opportunities for speciation.

The main difference between adaptive radiation and regular speciation is that adaptive radiation involves the rapid diversification of a single lineage into multiple new species, while regular speciation occurs when two or more separate lineages split into different species over a longer period of time.

Some key characteristics of adaptive radiation include:

1. Rapid diversification: Adaptive radiation involves the rapid formation of multiple new species within a relatively short period of time. This can result in the colonization of various ecological niches through the development of different traits and adaptations.

2. Ecological opportunity: Adaptive radiation often occurs when new ecological niches or habitats become available, allowing the ancestral species to exploit new resources and evolve new traits to survive and reproduce more effectively.

3. Trait divergence: During adaptive radiation, the ancestral species undergoes significant trait divergence as different populations adapt to different ecological niches. This leads to the development of distinct morphological, physiological, and behavioral characteristics in the newly formed species.

4. Parallel evolution: Adaptive radiation can result in the independent evolution of similar traits in different lineages as they adapt to similar ecological conditions. This can lead to the emergence of analogous structures or adaptations in unrelated species.

Overall, adaptive radiation is a process that allows for the rapid diversification of species, enabling them to occupy and exploit various ecological niches within a short period of time.