What is Evolution? What is Evolution by Natural Selection? What is the difference between the two? What is survival of the fittest?
Evolution by itself simply means change. In this context we are talking about slow change in the common characteristics of species.
Evolution by Natural Selection means change through the filter of survivability in the natural world. It is confusing because the word "Natural" carries the assumption that humans are somehow not a part of Nature, a leftover from the Medieval anthropocentric point of view.
A given species can contain a great deal of variation. Most species breed through sexual reproduction which mixes genes from each of the parents in a chaotic fashion, creating further variation. Others breed through cloning themselves, but they are usually smaller short-lived organisms where the variation is between the various strains any of which can die out without threatening the survivability of the species as a whole. Other variation occurs through changes in gene expression, mutation, and incorporation of bacterial and viral DNA. I use the term meme for this reproductive data rather than gene because some of this variation is contained in data that is not genetic.
Some explanations of evolution are confusing. "Survival of the fittest" is a phrase that makes it seem that it might be the organism's survival that is at stake. Of course it is not. It is the memes survival that is at stake. Look at Sickle Cell Anemia in humans. The genetic trait responsible for it may have evolved as a defense against Malaria, but it can cause illness and death as a side-effect - hardly matching the description of "Survival of the fittest". As long as the reproductive memes can be replicated it doesn't matter if the instances of an organism containing those memes appears fit or unfit.
"Natural Selection" makes it seem like there might be someone or some supernatural being doing the selection of which individuals or strains survive - despite the word "Natural". Evolution by Natural Selection arbitrarily precludes intentional intervention as in the case of the breeding of domesticated animals. This distinction clouds the issue. Hence I recommend dropping the term "Evolution by Natural Selection".
Instead, Evolution can be described as being a filtration process where some of the variation is filtered out because individuals carrying the memes simply didn't reproduce for some reason. The reason can be anything: infertility, chance, intentional intervention, and most importantly a statistical likelihood of the memes not making the individual survive in its particular circumstance. The result is those particular memes simply dying out and leaving other memes that might lead to a better chance of survival.
Evolution is best described as "Evolution by Meme Filtration" rather than "Evolution by Natural Selection" or "survival of the fittest".
No comments:
Post a Comment