Now, after three billion years, the Darwinian interlude is over. It was an interlude between two periods of horizontal gene transfer. The epoch of Darwinian evolution based on competition between species ended about ten thousand years ago when a single species, Homo Sapiens, began to dominate and reorganize the biosphere.
Since that time, cultural evolution has replaced biological evolution as the main driving force of change. Cultural evolution is not Darwinian. Cultures spread by horizontal transfer of ideas more than by genetic inheritance.
[ Very interesting... I'm very interested in a more complete development of this line of thinking... -k]
