Sent
to The Star, Johannesburg, Thu 01/12/2011 18:12, published less the blue paragraph
in The Star, December 8, 2011 as “Books reveal real process of
evolution”.
Seldom was the Star Letters
Editor's bias for religion against science more visible than in the Letters
page of Tuesday November 29, where religion gets 92 column cm (124 if one
counts the picture), and my viciously-slashed letter rates a mere 16 cm.
The Star should seriously
consider running a regular column to educate readers about science.
We would then be less
likely to get statements like Abraham Cohen's of November 24, naturally
applauded by Bob Holcombe (November 29), to the effect that evolution states
that the complexity of life came about in a single accident.
To see the real process,
please read two excellent books by evolutionary biologist Richard Dawkins,
"The Blind Watchmaker" and "Climbing Mount Improbable". Here is the tiniest of summaries:
The process of evolution
does rely on accidents, but that is only part of the process. There are three factors:
1) Genes reproduce with
amazing accuracy. Very few mistakes are
made, otherwise species would not be overwhelmingly stable.
2) Genes occasionally
change. Mutations do occur for various
reasons, though rarely.
3) Survival of the fittest.
Natural selection ruthlessly eliminates
changes that are not advantageous –most of them. The vast majority of known species are
extinct.
It is like a Lotto, but you
can keep your correct numbers. After a
few rounds you would have all winning numbers!
Thus evolution builds
continually on useful characteristics, constantly improving all species as they
fiercely compete.
Dawkins
likens it to a mountain with a steep cliff at the front. To leap from the bottom (the origin of life)
to the top (the complexity we see today) seems so incredible that people may
believe that it can only have happened by magic.
However,
if we look around the back of the mountain, we find gentle foothills with paths
meandering ever higher and leading gradually but eventually to the top. Thus evolution, by billions of years of slow
improvement, locking in useful attributes and discarding others, reaches the
improbable summit.
Note
that I said "meandering". We
carry in our bodies many of the blind choices that evolution made at the time,
features that no intelligent designer would make. So we have weak spines, strange neural paths,
appendices, tonsils, short lives, poor eyesight, only two hands, no wings, thin
skins, and can't digest cellulose, to name a few.
