Origin of Species Variorum

with the almost inevitable contingency of much extinction, explains the arrangement of all the forms of life, in groups subordinate to groups, all within a few great classes, which ... has prevailed throughout all time. This grand fact of the grouping of all organic beings under what is called the Natural System, is utterly inexplicable on the theory of creation.

As natural selection acts solely by accumulating slight, successive, favourable variations, it can produce no great or sudden modification; it can act only by .. short and slow steps. Hence the canon of "Natura non facit saltum," which every fresh addition to our knowledge tends to make truer, is on this theory .. intelligible. We can see why throughout nature the same general end is gained by an almost infinite diversity of means; for every peculiarity when once acquired is long inherited, and structures already diversified in many ways have to be adapted for the same general purpose. We can, in short, see why nature is prodigal in variety, though niggard in innovation. But why this should be a law of nature if each species had been independently created, no man can explain.

Many other facts are, as it seems to me, explicable on this theory. How strange it is that a bird, under the form of woodpecker, should have been created to prey on insects on the ground; that upland geese which never or rarely swim, should have been created with webbed feet; that a thrush-like bird should have been created to dive and feed on sub-aquatic insects; and that a petrel should have been created with the habits and structure fitting it for the life of an auk! .. and so .. in endless other cases. But on the view of each species constantly trying to increase in number, with natural selection always ready to adapt the slowly varying descendants of each to any unoccupied or ill-occu- pied