Seite - 151 - in The Origin of Species
Bild der Seite - 151 -
Text der Seite - 151 -
EFFECTS OF USE AND DISUSE 151
which subsists generally between the fauna of Europe and
of North America." On my view we must suppose that
American animals, having in most cases ordinary powers of
vision, slowly migrated by successive generations from the
outer world into the deeper and deeper recesses of the Ken-
tucky caves, as did European animals into the caves of
Europe. We have some evidence of this gradation of habit;
for, as Schiodte remarks, "We accordingly look upon the
subterranean faunas as small ramifications which have pene-
trated into the earth from the geographically limited faunas
of the adjacent tracts, and which, as they extended them-
selves into darkness, have been accommodated to surround-
ing circumstances. Animals not far remote from ordinary
forms, prepare the transition from light to darkness. Next
follow those that are constructed for twilight; and, last of
all, those destined for total darkness, and whose formation is
quite peculiar." These remarks of Schiodte's, it should be
understood, apply not to the same, but to distinct species.
By the time that an animal had reached, after numberless
generations, the deepest recesses, disuse will on this view
have more or less perfectly obliterated its eyes, and natural
selection will often have effected other changes, such as an
increase in the length of the antennae or palpi, as a compen-
sation for blindness. Notwithstanding such modifications,
we might expect still to see in the cave-animals of America,
affinities to the other inhabitants of that continent, and in
those of Europe to the inhabitants of the European conti-
nent. And this is the case with some of the American cave-
animals, as I hear from Professor Dana
; and some of the
European cave-insects are very closely allied to those of the
surrounding country. It would be difficult to give any ra-
tional explanation of the affinities of the blind cave-animals
to the other inhabitants of the two continents on the ordi-
nary view of their independent creation. That several of
the inhabitants of the caves of the Old and New Worlds
should be closely related, we might expect from the well-
known relationship of most of their other productions. As
a blind species of Bathyscia is found in abundance on shady
rocks far from caves, the loss of vision in the cave-species
of this one genus has probably had no relation to its dark
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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