"There are urges and urges; you are exploding with urges, desires. You don`t have one desire, you have many desires. Not only that you have many desires, you have contradictory desires. If one is fulfilled, the other, which is its contradiction, remains unfulfilled and you are in misery. If the other is fulfilled, then something else remains unfulfilled."

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Paleontologists had long been aware of a seeming contradiction between Darwin's postulate of gradualism, confirmed by the work of population genetics, and the actual findings of paleontology. Following phyletic lines through time seemed to reveal only minimal gradual changes but no clear evidence for any change of a species into a different genus or for the gradual origin of an evolutionary novelty. Anything truly novel always seemed to appear quite abruptly in the fossil record.

— Ernst Mayr