Evolution by Catastrophe: Does it indicate Intelligent Design? (cont.)
By Bibhu Dev Misra (IIT, IIM)
The 26 million year
cycle of mass extinction has significant implications for
evolutionary biology. As per Darwinism, the evolutionary process is
gradual, and takes place through ‘natural selection’.
Yet, the paleontological data tells us something quite different. In
addition, evolution seems to be guided by extraterrestrial factors.
The presence of enhanced levels of iridium in the soil layers at the
geological boundaries, as well as the discovery of impact craters on
the earth that match with the extinction periodicity, have convinced
scientists that the extinction events have been triggered by large
body impacts from outer space.
paleontologist at the University of Chicago, who along with Sepkoski
had identified the extinction periodicity in the fossil records,
implications of periodicity for evolutionary biology are profound.
The most obvious is that the evolutionary system is not ‘alone’
in the sense that it is partially dependent upon external influences
more profound than the local and regional environmental changes
normally considered... With kill rates for species estimated to have
been as high as 77% and 96% for the largest extinctions, the
biosphere is forced through narrow bottlenecks and the recovery from
these events is usually accompanied by fundamental changes in
biotic composition. Without these perturbations, the general
course of macroevolution could have been very different. ‘[i]
He further states that,
‘the largest mass extinctions produce major restructuring of
the biosphere wherein some successful groups are eliminated, allowing
previously minor groups to expand and diversify…There is
little evidence that extinction is selective in the positive sense
argued by Darwin. It has generally been impossible to predict,
before the fact, which species will be victims of an extinction