ABSTRACT
The human-caused extinction event gives cause for concern in that it threatens the nature we know and cherish. The threat is particularly serious because the replacement of species is becoming increasingly less possible. The central problem with the biological species concept is the confusion that abounds between classification of a species and a subspecies. Bradley Wilson's argument rests upon the likelihood that one or other of the gradualist or the punctuated equilibrium view of evolution is correct, and the understanding that 'if species are units of evolution, they must be reasonably discrete temporal entities that have the capacity to evolve'. The importance to conservation of relationship is evident in any ecology or conservation biology literature where there is much talk of relationship between species: predator and prey/host and parasite/decomposer and detrivore, as well as interspecific competition and mutualism.
