From the perspective of natural selection, changes in lineages due to unconscious or methodical selection are merely changes in which one of the most prominent selective pressures in the environment is human activity. It is not restricted, as we have seen, to domesticated species. Those white flags were too easy a target for hunters with guns, it seems. There is ever more accurate foresight, but even here, if we look closely at the practices in the laboratory, we will find a large measure of exploratory trial and error in their search of the best combinations of genes. We can use Darwin's three levels of genetic selection, plus our own fourth level, genetic engineering, as a model for four parallel levels of memetic selection in human culture.
Music is unique to our species, but found in every human culture.
It is manifestly complex, intricately designed, an expensive consumer of time, energy and materials. Here, then, is my Just-so Story, working gradually up Darwin's hierarchy of kinds of selection. Natural selection of musical memes. For no good reason at all . This was, you might say, mere nervous fidgeting, but the repetitive sounds striking his ears just happened to feel to him like a slight improvement on silence.