Seite - 445 - in The Origin of Species
Bild der Seite - 445 -
Text der Seite - 445 -
INHABITANTS OF ISLANDS 445
riod, and the existence at remote points of the world of
closely-allied species, is shown in another and more general
way. Mr. Gould remarked to me long ago, that in those
genera of birds which range over the world, many of the
species have very wide ranges. I can hardly doubt that this
rule is generally true, though difficult of proof. Amongst
mammals, we see it strikingly displayed in Bats, and In a
lesser degree in the Felidae and Canidae. We see the same
rule in the distribution of butterflies and beetles. So it is
with most of the inhabitants of fresh water, for many of the
genera in the most distinct classes range over the world, and
many of the species have enormous ranges. It is not meant
that all, but that some of the species have very wide ranges
in the genera which range very widely. Nor is it meant that
the species in such genera have on an average a very wide
range ; for this will largely depend on how far the process
of modification has gone; for instance, two varieties of the
same species inhabit America and Europe, and thus the spe-
cies has an immense range; but, if variation were to be car-
ried a little further, the two varieties would be ranked as
distinct species, and their range would be greatly reduced.
Still less is it meant, that species which have the capacity of
crossing barriers and ranging widely, as in the case of cer-
tain powerfully-winged birds, will necessarily range widely ;
for we should never forget that to range widely implies not
only the power of crossing barriers, but the more important
power of being victorious in distant lands in the struggle for
life with foreign associates. But according to the view that
all the species of a genus, though distributed to the most
remote points of the world, are descended from a single pro-
genitor, we ought to find, and I believe as a general rule we
do find, that some at least of the species range very widely.
We should bear in mind that many genera in all classes are
of ancient origin, and the species in this case will have had
ample time for dispersal and subsequent modification. There
is also reason to believe from geological evidence that within
each great class the lower organisms change at a slower rate
than the higher; consequently they will have had a better
chance of ranging widely and of still retaining the same spe-
cific character. This fact, together with that of the seeds
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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