By and large, the "experiments" that are performed are designed by
people who have accepted a neoDarwinistic explanation of life's
origins. It does not occur to them to explore the limits of
variation - because the theory does not encourage them to postulate
the existence of limits. This observation is sufficient to explain
why there is a lack of experimental data EITHER FOR OR AGAINST
limits.
Darwinism went through a crisis in the early part of the Twentieth
Century, because the science of genetics was developing, and it
appeared to explain away most, if not all, of Darwin's evidences of
variation. Observed variations due to artificial selection, such as
in dogs or pigeons, are irrelevant to evolutionary change, as no new
information is introduced. (I note Glenn's comments on dogs - but
remain unconvinced that any speciation has occurred!)
The thesis that there are no limits to variation is fundamental to
neoDarwinism - but it has been assumed as part of the framework of
knowledge. Very little testing of the of the fundamental assumptions
of neoDarwinism has taken place. Glenn needs to ask questions about
evidence for unlimited variation to neoDarwinists - this is vital
evidence for their theory! Without it, neoDarwinism is not truly a
science.
No scientific investigation has ever confirmed the assumption,
and what evidence there is suggests the contrary. One line of
evidence comes from the observation that all organs of animals
and plants are extraordinarily complex, and are composed of many
interrelated elements. Whether we think of the eye, the ear, the
nose, or any part of the body - a few mutations can be allowed,
but too many leads to the complete loss of function. The
mysterious complexity of living things is an indicator that
unlimited variation is not possible.
Plant and animal breeding programmes find that there are innate
limits: whether it be the level of sugar in sugar beet or the
milk production of cows. As organisms are pushed to the limits,
their systems become more delicate - and require greater input
from man to keep them alive and healthy. Significantly, the use
of irradiation to introduce innovation to breeding programmes (by
mutations) has never been popular. The results are generally of
transient value and breeders return to the traditional practices
of working with innate variation.
An unpublished PhD study in the UK considered cichlid fishes:
species from all over the world were collected for study and the
variations were analysed. They showed that an extraordinary
range of variations exist - but the picture is a mosaic involving
different combinations of a limited number of characters rather
than a spectrum of characters without restrictions. The
conclusion of the PhD was that the cichlids could be regarded as
a natural group: many species, but all genetically closely
related and limited in the range of variation they could exhibit.
This natural grouping is one of many. A widespread biological
phenomenon which is being missed by evolutionary biologists: they
are not looking for basic types so they do not see them!
Best wishes,
*** From David J. Tyler, CDT Department, Hollings Faculty,
Manchester Metropolitan University, UK.
Telephone: 0161-247-2636 ***