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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 71 of 119 (4/p)
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Export to Excel select * from OriginOfSpecies order by description desc limit 280, 4 (Page 71: Row)
subject
title
ordinal
description Desending Order (top row is last)
01 - Variations Under Domestication 01-10 - Methodical and Unconscious Selection 50 In plants the same gradual process of improvement, through the occasional preservation of the best individuals, whether or not sufficiently distinct to be ranked at their first appearance, as distinct varieties, and whether or not two or more species or races have become blended together by crossing, may plainly be recognised in the increased size and beauty which we now see in the varieties of the heartsease, rose, pelargonium, dahlia, and other plants, when compared with the older varieties or with their parent-stocks.

No one would ever expect to get a first-rate heartsease or dahlia from the seed of a wild plant.

heartsease
heartsease

rose
rose

pelargonium
pelargonium

dahlia
dahlia



No one would expect to raise a first-rate melting pear from the seed of the wild pear, though he might succeed from a poor seedling growing wild, if it had come from a garden-stock.

The pear, though cultivated in classical times, appears, from Pliny's description, to have been a fruit of very inferior quality.

I have seen great surprise expressed in horticultural works at the wonderful skill of gardeners, in having produced such splendid results from such poor materials; but the art has been simple, and, as far as the final result is concerned, has been followed almost unconsciously.

pear
pear


It has consisted in always cultivating the best-known variety, sowing its seeds, and, when a slightly better variety chanced to appear, selecting it, and so onwards.

But the gardeners of the classical period who cultivated the best pears which they could procure, never thought what splendid fruit we should eat; though we owe our excellent fruit in some small degree, to their having naturally chosen and preserved the best varieties they could anywhere find.
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 04-06 - On the generality of Intercross Between Individuals of the Same Species 20 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.

wolf
wolf


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.

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.
06 - Difficutiles in Theory 06-03 - Absence or Rarity of Transitional Varieties 40 In looking at species as they are now distributed over a wide area, we generally find them tolerably numerous over a large territory, then becoming somewhat abruptly rarer and rarer on the confines, and finally disappearing.

Hence the neutral territory between two representative species is generally narrow in comparison with the territory proper to each.

We see the same fact in ascending mountains, and sometimes it is quite remarkable how abruptly, as Alph. de Candolle has observed, a common alpine species disappears.
Alphonse de Candolle
Alphonse de Candolle


The same fact has been noticed by E. Forbes in sounding the depths of the sea with the dredge.
Edward Forbes
Edward Forbes


To those who look at climate and the physical conditions of life as the all-important elements of distribution, these facts ought to cause surprise, as climate and height or depth graduate away insensibly.

But when we bear in mind that almost every species, even in its metropolis, would increase immensely in numbers, were it not for other competing species; that nearly all either prey on or serve as prey for others; in short, that each organic being is either directly or indirectly related in the most important manner to other organic beings,- we see that the range of the inhabitants of any country by no means exclusively depends on insensibly changing physical conditions, but in a large part on the presence of other species, on which it lives, or by which it is destroyed, or with which it comes into competition; and as these species are already defined objects, not blending one into another by insensible gradations, the range of any one species, depending as does on the range of others, will tend to be sharply defined.

Moreover, each species on the confines of its range, where it exists in lessened numbers, will, during fluctuations in the number of its enemies or of its prey, or in the nature of the seasons, be extremely liable to utter extermination; and thus its geographical range will come to be still more sharply defined.