Good question--I think the first point to address is "a means to an end" seems to imply willful action. That is, evolution (according to Ridley) would be a conscious effort by a species to optimize the gene pool for survival of future generations; a rationalization for each species to mutate and diverge.
This is not the case, for a couple of reasons. First, evolution is largely due to environmental factors that exert much more control over the genetic drift of a species than any internal (i.e. willful) factors, such as sexual selection. Additionally, optimal performance is often sacrificed for the sake of reproduction (peacocks, now functionally flightless). All sexual selection happens in the context of the organism's environment--phentoypes can change, but if there's only one food source on your island, it's the limiting factor and will exert strong evolutionary pressure to maintain certain traits.
Second, no evolutionary trait is guaranteed to push the species towards a so-called optima. The influence of sexual selection on populations has left many species (again I lean on peacocks as an example) expending energy on developing traits that do not make them more viable or "optimized" as an organism, but instead make them more desirable mates and thus more likely to reproduce and pass on their genetic material. Peacocks could be much more resilient to predators without all that extra plumage, but they've traded off flight for mating success.
Finally, as an aside, evolution happens on such a large timescale that individual populations would barely be able to change their genetic makeup in the course of a single lifetime. This point is not as robust, but if general societal consensus was driving evolution, there would be extinct species littering the corners of the planet. Ridley seems to have missed the mark a little--nobody is doing anything to cause evolution; evolution happens to you over many years of mutations and environmental pressures.