Re: The "mechanism" of evolution
Karlin,
I don't doubt that genetic information changes over time. In particular when a male/female produce offpring, their children will inherit a mixture of their genes. That is why children are genetically different from their parents - because they contain a mixture of their genes. Now for the population as a whole, no new genetic information has been introduced - all that has happened is a mixing of existing genetic information. The only way new genetic information can be introduced is via random mutation. Now random mutation is extremely rare, is purely random, and even when it does occur is almost always destructive. Mutation destroys information, it can not create information. That is why you often get people with genetic diseases (negative random mutation) but you don't get superhumans with positive genetic mutations.
Let me give you an example. Take your favourite book. Now randomly choose a letter in that book. Now randomly choose a number between 1 and 26. Now change your chosen letter to the letter of the alphabet corresponding to the number you chose. Have you improved the book? Try it again. And again. What is the probability that you have improved the information in the book using this proceedure? Almost negligible. In fact the more you do this mutation, the more certain you can be that you are destroying information.
Random mutation destroys information. It does not and can not create information. Because it is random it is totally blind.
When you talk about adaptation, you have to be very careful. If a light skinned person (from a cold climate) emigrates to a hot country, their skin will darken somewhat. They have adapted. Yet nothing genetic or evolutionary has gone on. Adapatation also goes on at another level. Lets say there are two types of people - cold dwellers, and hot dwellers. Now lets say there is an ice age. This will favour the cold dwellers, and many of the hot dwellers will die out. Clearly some change has occured in the population, and the frequency of the various genes (there are more cold dwellers now). However *no new genetic information has been created*. Populations adapt to the enviorenment (via the frequency of various genes/characteristics), but no new species are created, and no new genetic information is created. Species can only go extinct. They can not emerge from nowhere.
The notion that evolution can take place over the course of 1 generation is known as Lamarckian evolution. It has been thoroughly discredited. Even the most ardent evolutionist would not defend such a debunked theory nowadays.
Similarly the notion that evolution can occur over a few generations can equally be dismissed. There just can't be enough genetic change over that period. Remember genes only change via the very rare occurence of random genetic mutation. Gentic mutation by definition must be a rare occurence because it is a mistake of nature. If you make too many mistakes you will not produce healthy offspring. Just like in the case of a book - if you change too many letters you will produce gobeldygook. So evolution over a few generations would require massive random mutation - which will be very destructive for the organism.
JV.