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The Origin of Species
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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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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

  1. EDITOR'S INTRODUCTION 5
  2. AN HISTORICAL SKETCH of the Progress of Opinion on the Origin of Species 9
  3. INTRODUCTION 21
  4. Variation under Domestication 25
  5. Variation under Nature 58
  6. Struggle for Existence 76
  7. Natural Selection; or the Survival of the Fittest 93
  8. Laws of Variation 145
  9. Difficulties of the Theory 178
  10. Miscellaneous Objections to the Theory of Natural Selection 219
  11. Instinct 262
  12. Hybridism 298
  13. On the Imperfection of the Geological Record 333
  14. On the Geological Succession of Organic Beinss 364
  15. Geographical Distribution 395
  16. Geographical Distribution - continued 427
  17. Mutual Affinities of Organic Beings: Morphology: Embryology: Rudimentary Organs 450
  18. Recapitulation and Conclusion 499
  19. GLOSSARY 531
  20. INDEX 541
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