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OriginOfSpecies - 475 Rows
Column Type #Values Column Stats
id int(11) 475 Column Stats
subject varchar(80) 14 Column Stats
title varchar(250) 139 Column Stats
ordinal int(11) 30 Column Stats
description text 474 Column Stats

475 rows, page 55 of 119 (4/p)
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Export to Excel select * from OriginOfSpecies order by ordinal desc limit 216, 4 (Page 55: Row)
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04 - Natural Selection 04-09 - Circumstances favourable for the production of new forms through Natural Selection 30 But we shall see in the sixth chapter that intermediate varieties, inhabiting intermediate districts, will in the long run generally be supplanted by one of the adjoining varieties.

Intercrossing will chiefly affect those animals which unite for each birth and wander much, and which do not breed at a very quick rate.

Hence with animals of this nature, for instance, birds, varieties will generally be confined to separated countries; and this I find to be the case.

With hermaphrodite organisms which cross only ccasionally, and likewise with animals which unite for each birth, but which wander little and can increase at a rapid rate, a new
and improved variety might be quickly formed on any one spot, and might there maintain itself in a body and afterwards spread, so that the individuals of the new variety would chiefly cross together.

On this principle, nurserymen always prefer saving seed from a large body of plants, as the chance of intercrossing is thus lessened.

snail
snail
04 - Natural Selection 04-11 - Divergence of Character 30 But how, it may be asked, can any analogous principle apply in nature?

I believe it can and does apply most efficiently (though it was a long time before I saw how), from the simple circumstance that the more diversified the descendants from any one species become in structure, constitution, and habits, by so much will they be better enabled to seize on many and widely diversified places in the polity of nature, and so be enabled to increase in numbers.
04 - Natural Selection 04-10 - Extinction caused by Natural Selection 30 From these several considerations I think it inevitably follows, that as new species in the course of time are formed through natural selection, others will become rarer and rarer, and finally extinct.

The forms which stand in closest competition with those undergoing modification and improvement will naturally suffer most.

And we have seen in the chapter on the Struggle for Existence that it is the most closely-allied forms,- varieties of the same species, and species of the same genus or of related genera,- which, from having nearly the same structure, constitution, and habits, generally come into the severest competition with each other; consequently, each new variety or species, during the progress of its formation, will generally press hardest on its nearest kindred, and tend to exterminate them.

We see the same process of extermination amongst our domesticated productions, through the selection of improved forms by man.

Many curious instances could be given showing how quickly new breeds of cattle, sheep, and other animals, and varieties of flowers, take the place of older and inferior kinds.

cattle
cattle

sheep
sheep


In Yorkshire, it is historically known that the ancient black cattle were displaced by the long-horns, and that these "were swept away by the shorthorns" (I quote the words of an agricultural writer) "as if by some murderous pestilence."
04 - Natural Selection 04-12 - On the Degree to which Organisation tends to advance 30 But we shall see how obscure this subject is if we look, for instance, to fishes, amongst which some naturalists rank those as highest which, like the sharks, approach nearest to amphibians; whilst other naturalists rank the common bony or teleostean fishes as the highest, inasmuch as they are most strictly fish-like and differ most from the other vertebrate classes.

shark
shark


We see still more plainly the obscurity of the subject by turning to plants, amongst which the standard of intellect is of course quite excluded; and here some botanists rank those plants as highest which have every organ, as sepals, petals, stamens, and pistils, fully developed in each flower; whereas other botanists, probably with more truth, look at the plants which have their several organs much modified and reduced in number as the highest.