monkeycousin

Essay, I think you may be talking a little over my head. I'm looking for documented evidence that a 1. A gene or group of genes has been shown to have been modified by environmental stress in a mature adult species and 2. that those altered genes were subsequently passed on to the offspring, and 3. that thereafter the altered gene continued to replicate in all subsequent offspring. If it happened millions of years ago, how would we know the difference between natural selection and this kind of environmental mutation? I am just trying to understand Evolution outside of natural selection if it exist. Since "gene therapy" is apparently a valid medical tool, I assume science must be capable of "unnatural" selection.

If I understand the basic premise of the theory of Evolution, it is clear enough to me how over thousands of generations a species will produce millions of variations in the individuals. A long period of time, perhaps 10's of thousands of generations, will yield billions of individuals, each with slight variations. So it is logical and natural to conclude that a particular habitat may favor the survival (to reproduction at least) of those species with variations that best suit their environment. So, again over thousands of generation, it is easy to see that the individuals least suited to the environment may not survive to the reproductive age. The characteristics of the survivors will be the only ones possible to replicate. I don't think anyone, no matter what philosophical opinion they may have toward the "theory" of Evolution can deny the idea of natural selection, or even "survival of the fittest" if you want to use the hot button term. If you admit that the individuals vary, sometimes drastically, from others of the same species, then it is only a matter of imagination and logic to realize that even after a few generations, many individuals will survive with characteristics in common enough to identify a "new' species. Darwin noticed this with the finch population on various islands in the Galapagos. But here is the question I would like answered. Can evolution be affected by a mutation of a gene after the species reaches the reproductive age? In other word, can radiation or diet or calamity, or therapy alter a gene after the species is an adult, and if so, can that mutated gene be passed on to another generation and all subsequent generations? Is there proof that it has happened in the past? If so, was the change significant?