Evolutionary radiation is a phenomenon in which a single lineage rapidly diversifies into many new species, often in response to new ecological opportunities or changes in the environment. It is an important driver of biodiversity and is responsible for the origin of many of the major groups of organisms that we see today.
One of the most famous examples of evolutionary radiation is the Cambrian explosion, which occurred approximately 541 million years ago and marks the earliest appearance of many of the major animal phyla. During this period, an incredible diversity of new body plans and ecological roles appeared in the fossil record, leading to the rapid radiation of life in the oceans.
Other examples of evolutionary radiations include the diversification of mammals following the extinction of the dinosaurs, the radiation of birds following the evolution of flight, and the diversification of flowering plants during the Cretaceous period. These radiations are often associated with key innovations or adaptations that allowed for the exploitation of new ecological niches.
Evolutionary radiations can also be influenced by a variety of factors, including geographic isolation, ecological specialization, and competition between closely related species. They can result in the formation of adaptive radiations, in which a group of species diversifies to exploit different parts of the environment, or non-adaptive radiations, in which species diversify without any clear ecological specialization.