Seite - 231 - in The Origin of Species
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Text der Seite - 231 -
THEORY OF NATURAL SELECTION 231
same manner; whilst the individuals, less favoured in the
same respects, will have been the most liable to perish.
We here see that there is no need to separate single pairs,
as man does, when he methodically improves a breed
; natural
selection will preserve and thus separate all the superior
individuals, allowing them freely to intercross, and will de-
stroy all the inferior individuals. By this process long-
continued, which exactly corresponds with what I have called
unconscious selection by man, combined no doubt in a most
important manner with the inherited effects of the increased
use of parts, it seems to me almost certain that an ordinary
hoofed quadruped might be converted into a giraffe.
To this conclusion Mr. Mivart brings forward two objec-
tions. One is that the increased size of the body would
obviously require an increased supply of food, and he con-
siders it as "very problematical whether the disadvantages
thence arising would not, in times of scarcity, more than
counterbalance the advantages." But as the giraffe does
actually exist in large numbers in S. Africa, and as some of
the largest antelopes in the world, taller than an ox, abound
there, why should we doubt that, as far as size is concerned,
intermediate gradations could formerly have existed there,
subjected as now to severe dearths? Assuredly the being
able to reach, at each stage of increased size, to a supply of
food, left untouched by the other hoofed quadrupeds of the
country, would have been of some advantage to the nascent
giraffe. Nor must we overlook the fact, that increased bulk
would act as a protection against almost all beasts of prey
excepting the lion
; and against this animal, its tall neck,—
and the taller the better,—would, as Mr. Chauncey Wright
has remarked, serve as a watch-tower. It is from this cause,
as Sir S. Baker remarks, that no animal is more difficult to
stalk than the giraffe. This animal also uses its long neck
as a means of offence or defence, by violently swinging its
head armed with stump-like horns. The preservation of
each species can rarely be determined by any one advantage
but by the union of all, great and small.
Mr. Mivart then asks (and this is his second objection),
if natural selection be so potent, and if high browsing be so
great an advantage, why has not any other hoofed quadruped
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Buch The Origin of Species"
The Origin of Species
- Titel
- The Origin of Species
- Autor
- Charles Darwin
- Verlag
- P. F. Collier & Son
- Ort
- New York
- Datum
- 1909
- Sprache
- englisch
- Lizenz
- PD
- Abmessungen
- 10.5 x 16.4 cm
- Seiten
- 568
- Schlagwörter
- Evolutionstheorie, Evolution, Theory of Evolution, Naturwissenschaft, Natural Sciences
- Kategorien
- International
- Naturwissenschaften Biologie
Inhaltsverzeichnis
- EDITOR'S INTRODUCTION 5
- AN HISTORICAL SKETCH of the Progress of Opinion on the Origin of Species 9
- INTRODUCTION 21
- Variation under Domestication 25
- Variation under Nature 58
- Struggle for Existence 76
- Natural Selection; or the Survival of the Fittest 93
- Laws of Variation 145
- Difficulties of the Theory 178
- Miscellaneous Objections to the Theory of Natural Selection 219
- Instinct 262
- Hybridism 298
- On the Imperfection of the Geological Record 333
- On the Geological Succession of Organic Beinss 364
- Geographical Distribution 395
- Geographical Distribution - continued 427
- Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs 450
- Recapitulation and Conclusion 499
- GLOSSARY 531
- INDEX 541