Following a mass extinction, what is the term for the process of new species development?

The process of new species development that follows a mass extinction is known as adaptive radiation. This occurs when organisms diversify rapidly into a variety of forms to adapt to different environments or ecological niches that become available after a significant disruption, such as a mass extinction event. The extinction eliminates many competing species, allowing the survivors to exploit new resources, leading to the emergence of new species.

During adaptive radiation, a common ancestor species evolves into multiple species, each adapted to specific environments or ways of life. This phenomenon has been documented in various groups, such as the finches of the Galápagos Islands, which evolved distinct characteristics based on their food sources and habitats.

In contrast, microevolution refers to small-scale changes within a species over time, while macroevolution involves larger-scale changes that can lead to the emergence of new species or broader taxonomic groups but is not specifically tied to the immediate aftermath of extinction events. Disruptive selection is a mode of natural selection that favors extreme traits over intermediate traits in a population, but it does not encompass the broader concept of speciation following a mass extinction.