Which of the following best summarizes the theory of punctuated equilibrium?
After periods of directional selection, the allelic frequencies in a population will reach equilibrium and then undergo disruptive selection.
Once one species achieves evolutionary dominance, all of the remaining species must compete among themselves for selective advantages; only then will the dominant species be challenged.
Most taxa experience relatively short periods during which they undergo rapid change, followed by relatively long periods during which they undergo relatively little change.
To ensure survival of the fittest, natural selection eliminates those species that disrupt the balance of nature.
Most species evolve gradually, with discrete changes appearing in the fossil record at short, regular intervals.