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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 22 of 119 (4/p)
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Export to Excel select * from OriginOfSpecies order by subject, title, ordinal limit 84, 4 (Page 22: Row)
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ordinal
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03 - Struggle for Existence 03-04 - Rapid Increase of naturalised Animals and Plants 20 In a state of nature almost every full-grown plant annually produces seed, and amongst animals there are very few which do not annually pair. Hence we may confidently assert, that all plants and animals are tending to increase at a geometrical ratio,- that all would rapidly stock every station in which they could anyhow exist,- and that this geometrical tendency to increase must. be checked by destruction at some period of life.

Our familiarity with the larger domestic animals tends, I think, to mislead us: we see no great destruction falling on them, but we do not keep in mind that thousands are annually slaughtered for food, and that in a state of nature an equal number would have somehow to be disposed of.
03 - Struggle for Existence 03-04 - Rapid Increase of naturalised Animals and Plants 30 The only difference between organisms which annually produce eggs or seeds by the thousand, and those which produce extremely few, is, that the slow-breeders would require a few more years to people, under favourable conditions, a whole district, let it be ever so large.

egg
egg


The condor lays a couple of eggs and the ostrich a score, and yet in the same country the condor may be the more numerous of the two; the Fulmar petrel lays but one egg, yet it is believed to be the most numerous bird in the world.

condor
condor

ostrich
ostrich

Fulmar Petrel
Fulmar Petrel


One fly deposits hundreds of eggs, and another, like the hippobosca, a single one; but this difference does not determine how many individuals of the two species can be supported in a district.

fly
fly

hippobosca
hippobosca


A large number of eggs is of some importance to those species which depend on a fluctuating amount of food, for it allows them rapidly to increase in number.

But the real importance of a large number of eggs or seeds is to make up for much destruction at some period of life; and this period in the great majority of cases is an early one.

If an animal can in any way protect its own eggs or young, a small number may be produced, and yet the average stock be fully kept up; but if many eggs or young are destroyed, many must be produced, or the species will become extinct.

It would suffice to keep up the full number of a tree, which lived on an average for a thousand years, if a single seed were produced once in a thousand years, supposing that this seed were never destroyed, and could be ensured to germinate in a fitting place. So that, in all cases, the average number of any animal or plant depends only indirectly on the number of its eggs or seeds.

tree
tree

seeds
seeds
03 - Struggle for Existence 03-05 - Nature of the Checks to Increase 10 In looking at Nature, it is most necessary to keep the foregoing considerations always in mind- never to forget that every single organic being may be said to be striving to the utmost to increase in numbers; that each lives by a struggle at some period of its life; that heavy destruction inevitably falls either on the young or old, during each generation or at recurrent intervals. Lighten any cheek, mitigate the destruction ever so little, and the number of the species will
almost instantaneously increase to any amount.
03 - Struggle for Existence 03-05 - Nature of the Checks to Increase 20 The causes which check the natural tendency of each species to increase are most obscure.

Look at the most vigorous species; by as much as it swarms in numbers, by so much will it tend to increase still further.

We know not exactly what the checks are even in a single
instance.

Nor will this surprise any one who reflects how ignorant we are on this head, even in regard to mankind, although so incomparably better known than any other animal.

This subject of the checks to increase has been ably treated by several authors, and I hope in a future work to discuss it at considerable length, more especially in regard to the feral animals of South America.

Mustang (Feral Horse)
Mustang (Feral Horse)

Feral Cat (re-homed)
Feral Cat (re-homed)


Here I will make only a few remarks, just to recall to the reader's mind some of the chief points.