Why evolution still exists if species do not evolve

Many evolutionary biologists and biophilosophers take species to be supraorganismic individuals, not classes or kinds of organisms. These species-as-individuals are usually regarded as the units of evolution. However, an analysis of the concept of evolution reveals that the very notion of evolution presupposes a concept of a species as a class or kind of organisms. Evolution is not mere quantitative or even qualitative change, but the coming into being of things of a new species. But if species are kinds of organisms, not things, then they do not evolve. That species must be conceived of as classes of organisms is further confirmed by the logical structure of classification. Thus, the unit of both evolution and classification is the organism: the organism is the carrier of qualitative novelty and it is the thing that is classified in biological systematics. This is not to deny that there are in fact supraorganismic individuals that are relevant to evolution, namely populations or reproductive communities as well as systems of such. Yet these must not be conflated with species. Once all these concepts are distinguished properly, it becomes clear in which sense we can say that species are not constant, even though they do not evolve, and that species are real, even though they are not material objects. The paper finally examines the role of populations in evolution, as well as some of the consequences of the view that species are classes for speciation theory and phylogenetic systematics.