@NealNealNeal,
NealNealNeal wrote:Natural Selection by mutations and survival of the fittest.
I'd say natural selection by means of survival of the fittest plus mutations, but I guess that is an adequate, albeit absolutely minimal definition.
To flesh it out further, in large populations, those creatures who are best able to survive do tend to survive more often statistically, so that there is a slow tendency for the successful genes to spread through the population and the inferior genes to be removed. Add to that, the fact that from time to time when an offspring is born there will be an error in inheritance of its genetic pattern (mutation), which is almost always harmful but occasionally helpful, then the result is that populations drift slowly toward greater and greater adaptation to their environments.
To give a specific example, if a bacterium which affects humans has a genetic error in reproduction which confers a greater ability, even very slightly greater, to resist an antibiotic in use, then statistically, there is a tendency of that trait to spread through the population, so that over many generations and with many mutations, the bacteria eventually develop the ability to survive the medicine.
Do you deny that this happens?