Natural Science Forum / Biology / Paleontology / January 2005

Missed this in my last reply. Evolution does not proceed by chance -
that is in fact the whole basis of the idea of natural selection. We
now know that genetic mutations arise randomly; this isn't disputable.
Natural selection acts on those mutations that provide individuals
with some slight benefit in their environment, and hence is dependent
on environmental conditions. That's why species in similar
environments tend to develop similar adaptations; if evolution were
random there would be no such thing as convergent evolution.

You're still missing the point of a scientific theory, however.
Scientists don't accept evolution because it's the perfect explanation
for everything biologists see (though to quote Dobhanzky, "nothing in
biology makes sense except in the light of evolution"), or because
absolutely everything predicted by evolution has been tested and
observed. You don't need to see a black hole or travel close to the
speed of light to accept relativity; relativity just needs to be able
to provide explanations for a broader range of phenomena than the
alternatives and not be disproved as new evidence comes to light. You
don't need to see the death of the universe to accept predictions
about the way it will happen. Similarly, you don't need to have seen
every extinct life form or every 'missing link' and you don't need to
wait for millions of years for wildly different new species to emerge
to accept evolution.

Scientists accept evolution in one form or another merely because it
is better at explaining observations than the alternative, some form
of spontaneous generation, such as creationism. Creation can't explain
the trends in taxonomy, the distribution of related life forms close
to one another but unrelated ones in similar habitats elsewhere, the
findings of genetics, the fossil record or observed changes in
species' physiology, behaviour or other characteristics. Scientists
accept evolution through natural selection because it's the most
plausible, and rigorously-tested, mechanism by which evolution can
occur.

Philip Bowles