Author of the Month

Evolution by Catastrophe: Does it indicate Intelligent Design? (cont.)
By Bibhu Dev Misra (IIT, IIM)

Raup’s observations that the extinction or survival of a species is a ‘chance’ event, is supported by the studies done by Macquarie University paleobiologist John Alroy. He says, ‘Mass extinction fundamentally changes the dynamics. It changes the composition of the biosphere forever. You can’t simply predict the winners and losers from what groups have done before’[iii]. The mass extinction event itself is short lived, very often below the resolving power of geologic record (<10,000 years), and possibly instantaneous.

Therefore, ‘Evolution by Catastrophe’ (a term used by Rampino in the ‘Encyclopedia of Planetary Sciences’) is in marked disagreement with standard Darwinian concepts of evolution. A new school of evolutionary thought, known as ‘Punctuated Equilibrium’ was developed independently by Harvard paleontologists Steven Jay Gould and Niles Eldredge (1972). They proposed that speciation occurs rapidly at times of environmental stress, and the long intervals (millions of years) between speciation are marked by general stasis, with little evolutionary change. Most species appear in the fossil record looking much the same as when they disappear. And in times of environmental stress, speciation happens abruptly within a space of a few thousand years. New species appear all at once and 'fully formed.'

Gould and Eldredge believe that speciation occurs so rapidly at times of stress that there is very little time for transitional forms to be fossilized. This is why we do not find any ‘missing links’ in the fossil data. In the 1970s, a number of examples of gradualism in the fossils were proposed by others in order to refute the concept of ‘punctuated equilibrium’. Gould and Eldredge dismissed these claims arguing ‘that virtually none of the examples brought forward to refute our model can stand as support for phyletic gradualism.’[iv]

PreviousPage 1Page 2Page 3Page 4Page 5Page 6Page 7Page 8Next


  1. Citations: “The Shifting Balance of Diversity Among Major Marine Animal Groups.” By J. Alroy. Science, Vol. 329 No. 5996, September 3, 2010 [back to text]
  2. Gould, S. J. and Eldredge, N., 1977. Punctuated equilibria: the tempo and mode of evolution reconsidered. Paleobiology, 3:115–151 (pp. 115) [back to text]

Site design by Amazing Internet Ltd, maintenance by Synchronicity. G+. Site privacy policy. Contact us.

Dedicated Servers and Cloud Servers by Gigenet. Invert Colour Scheme / Default