What is adaptive radiation?

Adaptive radiation refers to the rapid evolution of many species from a common ancestor, often in response to the availability of new ecological niches or environmental changes. This process allows species to diversify and adapt to various habitats, leading to a range of forms and functions that are suited to different environments. For instance, when a species colonizes a new area with diverse habitats, such as when Darwin's finches moved to the Galápagos Islands, they rapidly evolved into different species with varying beak shapes and sizes adapted to the different types of available food. This diversification helps to maximize ecological opportunities and minimize competition among species.

The other options represent different biological concepts. A period of major decline in species describes mass extinction events. The extinction of species due to environmental stress highlights how certain species may not cope with changing conditions. Slow genetic changes occurring in isolated populations pertain to the concept of gradual evolutionary change or speciation through mechanisms such as genetic drift and natural selection, but this does not capture the rapid diversification characteristic of adaptive radiation.