The central idea of sociobiology is that the emergence of social creatures (herd animals) coincided with the creation of what might be termed a socio-cultural environment. The socio-cultural environment is as much an environment that social creatures inhabited as the material environment. As social creatures evolve, two things happen to the socio-cultural environment:
As with evolution of species morphology, the maximum complexity of socio-cultural environments increases (there is selection pressure on the entire socio-cultural environment as, say, predators develop way of thwarting or exploiting the social aspect of their prey and the social species evolve to countervail this development, e.g. parasitic cordyceps and ants; that is, there is species-level selection, since a social characteristic unrecognized by a counterpart comes to nothing; consider this as an analogy for fourth generation warfare).
Subsequent generations of herd animals come to rely ever more heavily upon social cohesion — as opposed to horns, honed perceptive apparatus, efficient digestion, et cetera — as their primary means of survival.
As this socio-cultural environment becomes more sophisticated and intricate and increasingly important as a means of survival, the socio-cultural environment grows in importance as the universe of factors shaping the evolution of social animals, while the objective, geological, hydrological and biological environment recedes in its evolutionary force.
Sexual selection (a type of sociobiological selection, as opposed to natural or Malthusian selection) is the sort of selection pressure that a species faces when its fellows, rather than the environment becomes the main challenge to getting its genes into the future. The shifting balance of natural selection and sexual selection in the play of evolutionary forces is meta-evolutionary. Evolution is recursive, with developments in the subjects of evolution backpropigating into the mechanism itself. In this respect every new thing in the universe (or at least in the effective realm) can potentially alter the functioning of the evolutionary dynamic. In this broadened perspective, the idea of machine or meme evolution supplanting biological evolution should not be so surprising.
Among a certain sector of the wildly technologically enthusiastic (among whom I count myself, though Matthew Crawford’s Shop Class as Soulcraft: An Inquiry Into the Value of Work is presently doing a lot to kick the piss out of this pretention), there is a notion that humans are rapidly disencumbering themselves of the material world and constructing for ourselves a world of pure ideas, information, mind-stuff. At some point in human history saber-toothed tigers, virulent microbes, droughts and tar pits ceased to be the primary challenge to humans seeking to survive and reproduce. Such extra-human threats were replaced as the primary danger by human-originating threats such as careening contraptions, shoddy construction techniques, insufficient precaution with the kitchen fire, marauding hoplites, jilted dagger-wielding lovers, corrupt institutions and flawed regimes of succession in governance. It is at the point where today it is plausible that the human socio-cultural environment has attained a level of preponderance where even the level of environmental catastrophe such as an asteroid strike that caused the mass extinctions of the past might be thwarted by the constituents of the human socio-cultural environment (on the other hand, the complexity of our socio-cultural environment might be just the sort of run-away biological factor that caused past mass extinction such as the oxygen catastrophe or the Canfield ocean thesis of the Permian–Triassic extinction event). In this conception, it is usually the the information revolution, the invention of the computer — a brain-like device — that is the cause of this transcending of matter. The advent of technology was not the key turning point. The recognition of sociobiology is that this trend is an aspect of evolution; that it long predates not only technology, but also even predates humans. In this way, we are not unique, not the penultimate branch of the tree of life, but only the latest in a succession of forms.
Update, 15 September 2009: It’s worth noting that while computers are not the revolution, nor the source of the revolution, they do form a paradigm, shaping our conceptualizations in ways that allow us to perceive the revolution.