Page - 167 - in The Origin of Species
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Text of the Page - 167 -
SPECIFIC CHARACTERS HIGHLYVARIABLE 167
the two sexes of the same species. Sir J. Lubbock has re-
cently remarked, that several minute crustaceans offer ex-
cellent illustrations of this law. "In Pontella, for instance,
the sexual characters are afforded mainly by the anterior
antennas and by the fifth pair of legs: the specific differences
also are principally given by these organs." This relation
has a clear meaning on my view: I look at all the species
of the same genus as having as certainly descended from
a common progenitor, as have the two sexes of any one spe-
cies. Consequently, whatever part of the structure oi the
common progenitor, or of its early descendants, became vari-
ble, variations of this part would, it is highly probable, be
taken advantage of by natural and sexual selection, in order
to fit the several species to their several places in the econ-
omy of nature, and likewise to fit the two sexes of the same
species to each other, or to fit the males to struggle with
other males for the possession of the females.
Finally, then, I conclude that the greater variability of
specific characters, or those which distinguish species from
species, than of generic characters, or those which are pos-
sessed by all the species;—that the frequent extreme varia-
bility of any part which is developed in a species in an extra-
ordinary manner in comparison with the same part in its
congeners; and the slight degree of variability in a part,
however extraordinarily it may be developed, if it be com-
mon to a whole group of species;—that the great variability
of secondary sexual characters, and their great difference in
closely allied species;—that secondary sexual and ordinary
specific differences are generally displayed in the same parts
of the organisation,—are all principles closely connected to-
gether. All being mainly due to the species of the same
group being the descendants of a common progenitor, from
whom they have inherited much in common,—to parts which
have recently and largely varied being more likely still to go
on varying than parts which have long been inherited and
have not varied—to natural selection having more or less
completely, according to the lapse of time, overmastered the
tendency to reversion and to further variability, —to sexual
selection being less rigid than ordinary selection, —and to
back to the
book The Origin of Species"
The Origin of Species
- Title
- The Origin of Species
- Author
- Charles Darwin
- Publisher
- P. F. Collier & Son
- Location
- New York
- Date
- 1909
- Language
- English
- License
- PD
- Size
- 10.5 x 16.4 cm
- Pages
- 568
- Keywords
- Evolutionstheorie, Evolution, Theory of Evolution, Naturwissenschaft, Natural Sciences
- Categories
- International
- Naturwissenschaften Biologie
Table of contents
- 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