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Export to Excel select * from OriginOfSpecies where title = '04-11 - Divergence of Character' order by description limit 4 (Page 1: Row)
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04 - Natural Selection 04-11 - Divergence of Character 120 Full Size
If, then, these two varieties be variable, the most divergent of their variations will generally be preserved during the next thousand generations.

And after this interval, variety a1 is supposed in the diagram to have produced variety a2, which will, owing to the principle of divergence, differ more from (A) than did variety a1.

Variety m1 is supposed to have produced two varieties, namely m2 and s2, differing from each other, and more considerably from their common parent (A).

We may continue the process by similar steps for any length of time; some of the varieties, after each thousand generations, producing only a single variety, but in a more and more modified condition, some producing two or three varieties, and some failing to produce any.

Thus the varieties or modified descendants of the common parent (A), will generally go on increasing in number and diverging in character. In the diagram the process is represented up to the ten-thousandth generation, and under a condensed and simplified form up to the fourteen-thousandth generation.
04 - Natural Selection 04-11 - Divergence of Character 110 Full Size
The intervals between the horizontal lines in the diagram, may represent each a thousand or more generations.

After a thousand generations, species (A) is supposed to have produced two fairly well-marked varieties, namely a1 and m1.

These two varieties will generally still be exposed to the same conditions which made their parents variable, and the tendency to variability is in itself hereditary; consequently they will likewise tend to vary, and commonly in nearly the same manner as did their parents.

Moreover, these two varieties, being only slightly modified forms, will tend to inherit those advantages which made their parent (A) more numerous than most of the other inhabitants of the same country; they will also partake of those more general advantages which made the genus to which the parent-species belonged, a large genus in its own country.

And all these circumstances are favourable to the production of new varieties.
04 - Natural Selection 04-11 - Divergence of Character 150 After ten thousand generations, species (A) is supposed to have produced three forms, a10, f10, and m10 which, from having diverged in character during the successive generations, will have come to differ largely, but perhaps unequally, from each other and from their common parent.

If we suppose the amount of change between each horizontal line in our diagram to be excessively small, these three forms may still be only well-marked varieties; but we have only to suppose the steps in the process of modification to be more numerous or greater in amount, to convert these three forms into well-defined or at least into doubtful species.

Thus the diagram illustrates the steps by which the small differences distinguishing varieties are increased into the larger differences distinguishing species.
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By continuing the same process for a greater number of generations (as shown in the diagram in a condensed and simplified manner), we get eight species, marked by the letters between a14 and m14, all descended from (A). Thus, as I believe, species are multiplied and genera are formed.
04 - Natural Selection 04-11 - Divergence of Character 90 After the foregoing discussion, which has been much compressed, we may assume that the modified descendants of any one species will succeed so much the better as they become more diversified in structure, and are thus enabled to encroach on places occupied by other beings. Now let us see how this principle of benefit being derived from divergence of character, combined with the principles of natural selection and of extinction, tends to act.