The Origin of Species 



objects. Dominant species belonging to the 

 larger groups within each class tend to give birth 

 to new and dominant forms; so that each large 

 group tends to become still larger, and at the 

 same time more divergent in character. But as 

 all groups cannot thus go on increasing in size, 

 for the world .would not hold them, the more 

 dominant groups beat the less dominant. This 

 tendency in the large groups to go on increasing 

 in size and diverging in character, together with 

 the 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 accumulat- 

 ing slight, successive, favourable variations, it 

 can produce no great or sudden modifications; 

 it can act only by short and slow steps. Hence, 

 the canon of "Nature makes no leaps," which 

 every fresh addition to our knowledge tends to 

 confirm, 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 modified in 

 many different ways have to be adapted for the 

 same general purpose. We can, in short, see why 

 nature is prodigal in variety, though niggard in 

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