Catastrophism is the theory that the Earth has been affected in the past by sudden, short-lived, violent events, possibly worldwide in scope.[1] The dominant paradigm of modern geology is uniformitarianism (sometimes described as gradualism), in which slow incremental changes, such as erosion, create the Earth's appearance. This view holds that the present is the key to the past, and that all things continue as they were from the beginning of the world. Recently a more inclusive and integrated view of geologic events has developed, changing the scientific consensus to accept some catastrophic events in the geologic past. This held that there have been violent and sudden natural catastrophes such as great floods and the rapid formation of major mountain chains. Plants and animals living in those parts of the world where such events occurred were often killed off, according to the 19th-century French scientist Georges Cuvier. Then new life forms moved in from other areas. As a result, the fossil record for a region shows abrupt changes in species. Cuvier's explanation relied solely on scientific evidence rather than biblical interpretation.
Immanuel Velikovsky's
In the 1950s, Immanuel Velikovsky propounded catastrophism in several popular books. He speculated that the planet Venus is a former "comet" which was ejected from Jupiterand subsequently 3,500 years ago made two catastrophic close passes by Earth, 52 years apart, and later interacted with Mars, which then had a series of near collisions with Earth which ended in 687 B.C., before settling into its current orbit. Velikovsky used this to explain the biblical plagues of Egypt, the biblical reference to the "Sun standing still" for a day (Joshua 10:12 & 13, explained by changes in Earth's rotation), and the sinking of Atlantis. Scientists rejected Velikovsky's theories, often quite passionately.[11]
Modern theories also suggest that Earth's anomalously large moon was formed catastrophically. In a paper published in Icarus in 1975, William K. Hartmann and Donald R. Davisproposed that a catastrophic near-miss by a large planetesimal early in Earth's formation approximately 4.5 billion years ago blew out rocky debris, remelted Earth and formed theMoon, thus explaining the Moon's lesser density and lack of an iron core.[14] The impact theory does have some faults; some computer simulations show the formation of a ring or multiple moons post impact, and elements are not quite the same between the earth and moon
One of the key differences between catastrophism and uniformitarianism is that to function, uniformitarianism requires the assumption of vast time-lines, where as catastrophism can function with or without assumptions of long timelines.
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Geology and biology[edit]
In the natural sciences, gradualism is a theory which holds that profound change is the cumulative product of slow but continuous processes, often contrasted with catastrophism. The theory was proposed in 1795 by James Hutton, a Scottish physician and gentleman farmer, and was later incorporated into Charles Lyell's theory of uniformitarianism. Tenets from both theories were applied to biology and formed the basis of early evolutionary theory.
Charles Darwin was influenced by Lyell's Principles of Geology, which explained both uniformitarian methodology and theory. Using uniformitarianism, which states that one cannot make an appeal to any force or phenomenon which cannot presently be observed (seecatastrophism), Darwin theorized that the evolutionary process must occur gradually, not in saltations, since saltations are not presently observed, and extreme deviations from the usual phenotypic variation would be more likely to be selected against.
Gradualism is often confused with the concept of phyletic gradualism. It is a term coined by Stephen Jay Gould and Niles Eldredge to contrast with their model of punctuated equilibrium, which is gradualist itself, but argues that most evolution is marked by long periods of evolutionary stability (called stasis), which is punctuated by rare instances of branching evolution.[2]