Seite - 332 - in The Origin of Species
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332 ORIGIN OF SPECIES
the systematic affinity of the forms subjected to experiment;
for systematic affinity includes resemblances of all kinds.
First crosses between forms known to be varieties, or suffi-
ciently alike to be considered as varieties, and their mon-
grel offspring, are very generally, but not, as is so often
stated, invariably fertile. Nor is this almost universal and
perfect fertility surprising, when it is remembered how
liable we are to argue in a circle with respect to varieties
in a state of nature
; and when we remember that the greater
number of varieties have been produced under domestication
by the selection of mere external differences, and that they
have not been long exposed to uniform conditions of life. It
should also be especially kept in mind, that long-continued
domestication tends to eliminate sterility, and is therefore
little likely to induce this same quality. Independently of the
question of fertility, in all other respects there is the closest
general resemblance between hybrids and mongrels,—in their
variability, in their power of absorbing each other by re-
peated crosses, and in their inheritance of characters from
both parent-forms. Finally, then, although we are as ig-
norant of the precise cause of the sterility of first crosses
and of hybrids as we are why animals and plants removed
from their natural conditions become sterile, yet the facts
given in this chapter do not seem to me opposed to the belief
that species aboriginally existed as varieties.
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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