Concept 22.1: The Darwinian revolution challenged traditional views of a young Earth inhabited by unchanging species • Describe the theories of catastrophism, gradualism, and uniformitarianism. • Explain the mechanism for evolutionary change proposed by Jean-Baptiste de Lamarck

Catastrophism is a theory developed by Georges Cuvier that states that natural history has been punctuated by catastrophic events that altered the way live developed. Gradualism is a theory that stipulates that changes of organic life and earth itself occur through gradual increments with transitions that are slow rather than periodic and rapid. Uniformitarianism suggests that the Earth's geological processes acted in the same manner in the same intensity in the past as they do in the present and that such uniformity is accountable for all the geologic change.
Jean-Baptiste de Lamarck's theory proposes a change through use and disuse when environments changed, organisms had to change their behavior to survive, if they began to use an organ more often it would increase their lifetime and their offspring will inherit this modified organ. As these organisms adapted, nature also drove them from simple forms to increasingly complex ones.

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