Quote Originally Posted by Sharla
Bilbo I am a biological scientist with a background in molecular biology and Botany and i disagree with you. Molecular biology supports the theory of evolution. DNA changes naturally and easily by a number of processes including crossing over and recombination. They are always involved in any sexual reproduction.

It's not only the absence or presence of a gene that dictates a trait but it's level of expression. A little growth hormone = a little growth - a lot = a lot. This can be altered by changing just one base pair in the activation site of a transcription factor. Small changes in DNA can have huge effects.

All you have to see to know that is the difference between parents and their children. Variation is natural. It'd be weird to be the exact clone of your parent because that never happens.

Not all changes to DNA are beneficial of course and I'm sure that the larger nose I have than my mother will not help me pass my genes onto the next generation. thus not all changes in the DNA code are improvements or continue to be inherited but they don't all have to be.

The random part is taken out by a selection pressure which will deem a trait an advantage or disadvantage according to whether or not the gene carrier will have to opportunity to procreate.
The kind of changes you are talking about however are not evolution on a macro scale. I completely agree with the validity of natural selection as identified by Darwin but I am totally unconvinced in his claim that natural selection can lead to evolution.

As a biologist you will be able to correct me if I'm wrong but my understanding is that whatever changes happen in any organism, be it a dog, a plant or somebody's daughter the genetic information must be already present within the DNA of the organism in question.

So a dog can through selective breeding, or through enviromental pressures undergo considerable change in size, colour, behaviour etc as certain traits are isolated and encouraged. So for example birds on a remote island may lose the ability to fly over time as survival favours those who are unable to get lost at sea, or a species of cave fish might lose its sight over time as it becomes unneccessary, or some species in a remote location may shrink in size to cope with lack of food etc.

But none of this is macro evolution in the molecules to man sense. All of the information necessary to make these changes was always present in the species and it's just a case of jiggling lines of code so to speak rather than creating new information.

Experiments of zapping fruit flies with high levels of radiation produced a series of bizarre flies some with many pairs of wings, extra legs, different sizes etc. However life expectancy was reduced in all cases and as soon as the treatment was stopped the flies returned to a normal state in just a few generations suggesting that organisms resist change rather than respond to it.

It seems to me that scientist make exactly the same kind of leap of faith that religious believers do, in that through an act of faith they believe in spite of a total lack of evidence that these little changes brought about by natural selection can be a catalyst for macro evolution on a molecule to man scale.


cc though for an interesting discussion, it's nice to meet someone who works within the molecular sciences, I find the whole subject of creation vs evolution a fascinating one and it's rare to meet someone who has an extensive knowledge