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164 ORIGIN OF SPECIES
cease; and that the most abnormally developed organs may
be made constant, I see no reason to doubt. Hence, when
an organ, however abnormal it may be, has been transmitted
in approximately the same condition to many modified de-
scendants, as in the case of the wing of the bat, it must have
existed, according to our theory, for an immense period in
nearly the same state; and thus it has come not to be more
variable than any other structure. It is only in those cases
in which the modification has been comparatively recent and
extraordinarily great that we ought to find the generative
variability, as it may be called, still present in a high degree.
For in this case the variability will seldom as yet have been
fixed by the continued selection of the individuals varying
in the required manner and degree, and by the continued
rejection of those tending to revert to a former and less-
modified condition.
SPECIFIC CHARACTERS MORE VARIABLE THAN GENERIC
CHARACTERS
The principle discussed under the last heading may be
applied to our present subject. It is notorious that specific
characters are more variable than generic. To explain by a
simple example what is meant: if in a large genus of plants
some species had blue flowers and some had red, the colour
would be only a specific character, and no one would be sur-
prised at one of the blue species varying into red, or con-
versely; but if all the species had blue flowers, the colour
would become a generic character, and its variation would
be a more unusual circumstance. I have chosen this exam-
ple because the explanation which most naturalists would
advance is not here applicable, namely, that specific charac-
ters are more variable than generic, because they are taken
from parts of less physiological importance than those com-
monly used for classing genera. I believe this explanation
is partly, yet only indirectly, true; I shall, however, have to
return to this point in the chapter on Classification. It would
be almost superfluous to adduce evidence in support of the
statement, that ordinary specific characters are more variable
than generic; but with respect to important characters, I
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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