Origin of Species Variorum

→ p 14 , 1859 1861 1866 1869 1872

p 14 1860

→ f 14 , 1859 1861 1866 1869 1872

f 14 1860

→ m 14 , 1859 1861 1866 1869 1872

m 14 1860

→ differing 1869 1872

and as these latter two genera, both from continued divergence of character and from inheritance from a different parent, will differ 1859 1860 1861 1866

→ descendants of (A). These two 1869 1872

three genera descended from (A), the two little 1859 1860 1861 1866

→ some 1869 1872

one species of a 1859 1860 1861 1866

→ have as yet 1872

as yet have 1859 1860 1861 1866 1869

→ as, according to 1872

on 1859 1860 1861 1866

as according to 1869

I see no reason to limit the process of modification, as now explained, to the formation of genera alone. If, in

our

the

diagram, we suppose the amount of change represented by each successive group of diverging dotted lines to be

very

....

great, the forms marked a 14 to → p 14 ,

, those

those

marked b 14 and → f 14 ,

, and

and

those marked o 14 to → m 14 ,

, will

will

form three very distinct genera. We shall also have two very distinct genera descended from

(I);

(I),

→differing widely from the →descendants of (A). These two groups of genera will

form

thus form

two distinct families, or

even

....

orders, according to the amount of divergent modification supposed to be represented in the diagram. And the two new families, or orders,

will have

are

descended from two species of the original

genus;

genus,

and these

two species

....

are supposed to

have

descended from →some still more ancient and unknown

genus.

form.

We have seen that in each country it is the species

belonging to

the larger genera which oftenest present varieties or incipient species. This, indeed, might have been expected;

for

for,

as natural selection acts through one form having some advantage over other forms in the struggle for existence, it will chiefly act on those which already have some advantage; and the largeness of any group shows that its species have inherited from a common ancestor some advantage in common. Hence, the struggle for the production of new and modified

descendants,

descendants

will mainly lie between the larger

groups,

groups

which are all trying to increase in number. One large group will slowly conquer another large group, reduce its numbers, and thus lessen its chance of further variation and improvement. Within the same large group, the later and more highly perfected sub-groups, from branching out and seizing on many new places in the polity of Nature, will constantly tend to supplant and destroy the earlier and less improved sub-groups. Small and broken groups and sub-groups will finally

tend to

....

disappear. Looking to the future, we can predict that the groups of organic beings which are now large and triumphant, and which are least broken up, that is, which →have as yet suffered least extinction,

will

will,

for a long

period

period,

continue to increase. But which groups will ultimately prevail, no man can predict; for we

well

....

know that many groups, formerly most extensively developed, have now become extinct. Looking still more remotely to the future, we may predict

that

that,

owing to the continued and steady increase of the larger groups, a multitude of smaller groups will become utterly extinct, and leave no modified descendants; and consequently

that

that,

of the species living at any one period, extremely few will transmit descendants to a remote futurity. I shall have to return to this subject in the chapter on Classification, but I may add that →as, according to this

view

view,

....

extremely few of the more