An evolutionary radiation is an increase in taxonomic diversity that is caused by elevated rates of speciation,[1] that may or may not be associated with an increase in morphological disparity.[2] A significantly large and diverse radiation within a relatively short geologic time scale (e.g. a period or epoch) is often referred to as an explosion. Radiations may affect one clade or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment, they are termed adaptive radiations.[3]