Seite - 155 - in The Origin of Species
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Text der Seite - 155 -
CORRELATED VARIATION 155
kidney-bean has been often cited for a similar purpose, and
with much greater weight; but until someone will sow,'dur-
ing a score of generations, his kidney-beans so early that a
very large proportion are destroyed by frost, and then collect
seed from the few survivors, with care to prevent accidental
crosses, and then again get seed from these seedlings, with
the same precautions, the experiment cannot be said to have
been tried. Nor let it be supposed that differences in the con-
stitution of seedling kidney-beans never appear, for an ac-
count has been published how much more hardy some seed-
lings are than others; and of this fact I have myself ob-
served striking instances.
On the whole, we may conclude that habit, or use and
disuse, have, in some cases, played a considerable part in the
modification of the constitution and structure
; but that the
effects have often been largely combined with, and some-
times overmastered by, the natural selection of innate
variations.
CORRELATED VARIATION
I mean by this expression that the whole organisation is
so tied together during its growth and development, that
when slight variations in any one part occur, and are accu-
mulated through natural selection, other parts become modi-
fied. This is a very important subject, most imperfectly
understood, and no doubt wholly dift'ercnt classes of facts
may be here easily confounded together. We shall presently
see that simple inheritance often gives the false appearance
of correlation. One of the most obvious real cases is, that
variations of structure arising in the young or larvre nat-
urally tend to affect the structure of the mature animal.
The several parts of the body which are homologous, and
which, at an early embryonic period, are identical in struc-_
ture, and which are necessarily exposed to similar condi-
tions, seem eminently liable to vary in a like manner: we see
this in the right and left sides of the body varying in the
same manner; in the front and hind legs, and even in the
jaws and limbs, varying together, for the lower jaw is be-
lieved by some anatomists to be homologous with the limbs.
These tendencies, I do not doubt, may be mastered more or
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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