Laughing Coyote
Member
This quote asserts that mutations are random, something that no biologist would deny. But then what is the thought process that leads you to deduce from that statement that evolution (from the Latin for "unrolling") is itself random?
Mutations may be seen as the manner that new traits or modifications are entered into the genomes of populations. The actual process of how these "unroll" in new forms of life however results from a kind of selection, which is not random at all. Without mutation and a number of other processes of exchange of genetic material within and between organisms, no life would have ever developed because nothing new could have been generated. On the other hand, though this constant creation of new raw materials from within existing ones is essential to how life unrolls or evolves, it does not tell us how it comes about.
Yes one could say that God or beings from outer space intervene, but then you are entering something from the outside which itself has to be explained. Perhaps we tend to think that way because we humans are always intervening in other things on our planet. But there is nothing to indicate that we aren't product of the same planet, and then everything else seems to be messing with us as well (for example what we call weeds, pests, pathogens, and not to forget domesticated cats). That natural selection requires no outside intervention and is derived from a few simple principles, allows all forms of life to be explained within one framework. Any kind of outside explanation in contrast requires adding more and more exceptions and rules to the explanation, somewhat in the manner that all kinds of amendments had to be added to a model of the solar system in which the earth was thought to be center in order to explain motions of the planets and other heavenly bodies that should not have happened in such a model.
Mutation alone would no more give proof to evolution than the fact that the materials made available in different locations could indicate how people developed the means to turn these into different kinds of houses. Nor would it explain why different groups of people in the same location build different kinds of houses.
In life, how this came about is what Darwin called "natural selection." Note he did not call it natural randomness. He developed it without even knowing of mutation, except as the appearance of changes so obvious that they were called "monstrosities" at the time. All he saw was evidence that more and more new varieties of life with more and more new traits were appearing over time in the manner of the unending growth and branching of a tree. Most changes taking place in populations of organisms, however, are so gradual and subtle that neither they nor their effects are easily noticed from generation to generation, except to the extent that they give such advantage that organisms carrying the changes will have more children and those more children in each generation than those without it, causing carriers to represent a greater and greater percentage of the population. Imagine the acquisition over time simultaneously of increasing numbers of such changes, causing all kinds of divergences in any population.
Look at all the kinds of dogs that came just from wolves, when their interbreeding was controlled by humans over the course of a mere 15 thousand years or less; or all different varieties of humans since they came out of Africa just within 300 thousand years (according to the latest evidence). Darwin used the analogy of our own selection of variety in domestic plants and animals as an analogy for how in nature, the appearance of new features affects the reproductive rate of descendants of different individuals in the population, leading them gradually over time to supplant other groups or else diverge within and across the landscape according to their migrations and the tendencies provided by their increasingly different capabilities.
And regarding proof, your friend did you a disservice if he said science "proves" things, because proof would require full knowledge of all variables involved, which is impossible. Science is a procedure for discovering and isolating variables, and making and testing assumptions or hypotheses or stories we have of the world and universe to better understand them and ourselves. It is what humans have done through time, with the primary difference being that science has developed a systematization of the testing, verifying, unifying, integration, analyzing, observing, proposing, and of the communication and acceptance of the many results of this testing within increasingly unified frameworks of understanding. As it engages with the world and is subject to human thought, furthermore, it also changes -- and so will it continue to change.
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