A species is a reproductive community of populations reproductively isolated from others that occupies a specific niche in nature.

Evolution thus is merely contingent on certain processes articulated by Darwin: variation and selection.

Evolution, thus, is merely contingent on certain processes articulated by Darwin: variation and selection. No longer is a fixed object transformed, as in transformational evolution, but an entirely new start is, so to speak, made in every generation.

There is more to biology than rats, Drosophila, Caenorhabditis, and E. coli.

A species consists of a group of populations which replace each other geographically or ecologically and of which the neighboring ones integrate or hybridise wherever they are in contact or which are potentially capable of doing so (with one or more of the populations) in those cases where contact is prevented by geographical or ecological barriers.

It seems to me that for Darwin the pulsing of evolutionary rates was a strictly vertical phenomenon.

A species is a reproductive community of populations reproductively isolated from others that occupies a specific niche in nature.