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133 rows, page 10 of 34 (4/p)
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Export to Excel select * from OriginOfSpecies where ordinal = '10' order by subject limit 36, 4 (Page 10: Row)
subject Desending Order (top row is first)
title
ordinal
description
04 - Natural Selection 04-02 - Its Power Compared with Man's Selection 10 As man can produce a great result with his domestic animals and plants by adding up in any given direction individual differences, so could natural selection, but far more easily from having incomparably longer time for action.

Nor do I believe that any great physical change, as of climate, or any unusual degree of isolation to check immigration, is necessary in order that new and unoccupied places should be left, for natural selection to fill up by improving some of the varying inhabitants.

For as all the inhabitants of each country are struggling together with nicely balanced forces, extremely slight modifications in the structure or habits of one species would often give it an advantage over others; and still further modifications of the same kind would often still further increase the advantage, as long as the species continued under the same conditions of life and profited by similar
means of subsistence and defence.

No country can be named in which all the native inhabitants are now so perfectly adapted to each other and to the physical conditions under which they live, that none of them could be still better adapted or improved; for in all countries, the natives have been so far conquered by naturalised productions, that they have allowed some foreigners to take firm possession of the land.

And as foreigners have thus in every country beaten some of the natives, we may safely conclude that the natives might have been modified with advantage, so as to have better resisted the intruders.
04 - Natural Selection 04-06 - On the generality of Intercross Between Individuals of the Same Species 10 Illustrations of the Action of Natural Selection:
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04 - Natural Selection 04-07 - Illustrations of the Action of Natural Selection: 10 In order to make it clear how, as I believe, natural selection acts, I must beg permission to give one or two imaginary illustrations.

Let us take the case of a wolf, which preys on various animals, securing some by craft, some by strength, and some by fleetness; and let us suppose that the fleetest prey, a deer for instance, had from any change in the country increased in numbers, or that other prey had decreased in numbers, during that season of the year when the wolf was hardest pressed for food. Under such circumstances the swiftest and slimmest wolves would have the best chance of surviving and so be preserved or selected,- provided always that they retained strength to master their prey at this or some other period of the year, when they were compelled to prey on other animals.

wolf
wolf

deer
deer


I can see no more reason to doubt that this would be the result, than that man should be able to improve the fleetness of his greyhounds by careful and methodical selection, or by that kind of unconscious selection which follows from each man trying to keep the best dogs without any thought of modifying the breed.

dog
dog
04 - Natural Selection 04-09 - Circumstances favourable for the production of new forms through Natural Selection 10 This is an extremely intricate subject.

A great amount of variability, under which term individual differences are always included, will evidently be favourable.

A large number of individuals, by giving a better chance within any given period for the appearance of profitable variations, will compensate for a lesser amount of variability in each individual, and is, I believe, a highly important element of success.

Though Nature grants long periods of time for the work of natural selection, she does not grant an indefinite period; for as all organic beings are striving to seize on each place in the economy of nature, if any one species does not become modified and improved in a corresponding degree with its competitors, it will be exterminated.

Cheetah
Cheetah