Wednesday, February 22, 2006
Beware the IDs of non biologists
Saw the guy behind the anti-evolution organisation, Access Research Network
on TV a month or two ago. Well funded by all accounts.
This interview with the late mathematician Marcel-Paul Schützenberger
comes from there.
I've got to the bit where he says
Darwinists imagine that it requires what? A thousand or two thousand genes to assemble an eye, the specification of the organ thus requiring one or two thousand units of information? This is absurd!And am now on full alert....
At the most basic one can see though something like explaining consciousness is fraught with difficulties (the hard and the otherwise problem, etc), the evolutionary mechanism is a balance between maintaining the consistency of form and function while allowing for change. The whole of biochemistry and physiology works on a feedback system which is not unlike a sophisticated computer programme with the proviso that the programmer is in there too, patching and adding new sections of code, as it were, according to changing circumstances. Although when one considers the everyday, but complex, functioning of an organ such as the liver, it does become a wonder as to how, qua evolution and the formation of new species, one can continue to have a fully functioning liver which serves the organism it is in, as it should, and to to have the subtle changes required for it to serve the changing needs of the organism (new species or developing species in the offing as well) in relation to its environment.
This brings me to something learnt as a student: Principles of taxonomy/Taxonomy and Evolution. Dr. Garth Underwood,[ Garth Leon Underwood 1919–2002 ] University of West Indies, British Museum, expert herpetologist. Still have his notes (17.11.72, etc.). For example a simple check list
Taxonomic characteristics
Anatomical
Gross
Microscopical
Ultramicroscopical
Physiological
Biochemical; including serological
Genetical; including chromosomes
Ecological
Behavioural
Devlopmental
Separate characters
correlated characters
Inapplicable characters
Pleiotropism [genes produce effects not related to one another but which have the same genetic basis]
Allometry [tying together of two characters developmentally e.g. Deers antlers and size of body – so not separate characters]
Character states
Two state characters
Multiple state characters
Quantitiative characters
Merietic[always have 11 teeth not 11 1/2
Continuously variable [adult size is extremely variable: can group the sizew into various categories]
Proportions
Environmental influence
show how sophisticated it all is.
He showed in his marvellous lectures how one species of snake (his specialism) was distinguished from another often initally only through minute variations skull plate structure. Other differences might then be discovered, such as serum. Even then there might be disputes as to whether A and B were distinct species or varieties of the same one. The more biochemical or physiological differences emerging would firm it up.
Another lesson in all this is from animals such as birds and insects which again might not be significantly different form, but have behavioural charecteristics which defined their specieshood. Species A has one type of song (and that could be a bird song or a cricket stridulation). If I remember correctly (better read up some of those notes) you could get intermediates, but how that worked, qua species, I can't remember. Though in the end it is whether they interbred which counted evolutionarily. Gene pools. But even the notion that two insects do not mate if they fail to recognise or respond to subtly different but not dissimilar calls is easy to grasp. Its not all about gross morphology or some sort of physiological incompatibility that might prevent fertilisation.
While in a sense evolution happens at the individual level, since it is the changes at each meiosis and the combination of complementary set of genes at fertilisation which are what is passed on, and both transmit differences and end up regulating the integrity of the species, evolution is also studied in population terms.
// posted by Adfero Affero @ Wednesday, February 22, 2006 
