Final answer:
Extinction bursts are temporary increases in behavior that occur when a previously reinforced behavior is no longer reinforced. It is an observable phenomenon in the study of behavior and not fictional.
Step-by-step explanation:
Extinction bursts are temporary increases in the frequency, intensity, or variability of a behavior that occurs when a reinforcement for that behavior is removed. The phenomenon occurs because the subject, whether an animal or a human, is attempting to regain the reinforcement that they are used to receiving. This increase in behavior is generally short-lived, as the subject eventually adjusts to the new scenario where the reinforcement is no longer available. It is not a fictional concept but a well-observed phenomenon within the study of behavior.
An adaptive radiation, on the other hand, is a burst of speciation, where a single or a few species rapidly diversify into a large number of descendant species that are often adapted to a wide range of environments.
Current rates of extinction are considered higher than background extinction rates, and speciation is indeed the process by which new species are created. However, all living things are classified into one of three taxonomic domains, not four.