The Origin of Species by Means of Natural Selection: Or, the Preservation of Favored Races in the Struggle for Life, Volumen1D. Appleton, 1898 |
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Página v
... Difficulty of distinguishing between Varieties and Species - Origin of domestic varieties from one or more species - Domestic Pigeons , their Differences and Origin- Principles of Selection , anciently followed , their Effects ...
... Difficulty of distinguishing between Varieties and Species - Origin of domestic varieties from one or more species - Domestic Pigeons , their Differences and Origin- Principles of Selection , anciently followed , their Effects ...
Página vii
... DIFFICULTIES OF THE THEORY . Difficulties of the theory of descent with modification - Absence or rarity of ... difficulty - Natura non facit saltum - Organs of small importance - Organs not in all cases absolutely perfect - The ...
... DIFFICULTIES OF THE THEORY . Difficulties of the theory of descent with modification - Absence or rarity of ... difficulty - Natura non facit saltum - Organs of small importance - Organs not in all cases absolutely perfect - The ...
Página viii
... structure not necessarily simultaneous - Difficulties of the theory of the Natural Selection of instincts - Neuter or sterile insects Summary . Page 319 ADDITIONS AND CORRECTIONS TO THE SIXTH EDITION . NUMEROUS small. viii CONTENTS .
... structure not necessarily simultaneous - Difficulties of the theory of the Natural Selection of instincts - Neuter or sterile insects Summary . Page 319 ADDITIONS AND CORRECTIONS TO THE SIXTH EDITION . NUMEROUS small. viii CONTENTS .
Página xiv
... difficulty of distinguishing species and varieties , by the almost perfect gradation of forms in certain groups , and by the analogy of domestic produc- tions . With respect to the means of modification , he attributed something to the ...
... difficulty of distinguishing species and varieties , by the almost perfect gradation of forms in certain groups , and by the analogy of domestic produc- tions . With respect to the means of modification , he attributed something to the ...
Página xix
... difficulty in ascertaining affini- ties ; second , of another impulse connected with the vital forces , tending , in the course of generations , to modify organic structures in accordance with external circumstances , as food , the ...
... difficulty in ascertaining affini- ties ; second , of another impulse connected with the vital forces , tending , in the course of generations , to modify organic structures in accordance with external circumstances , as food , the ...
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Términos y frases comunes
adapted advantage allied analogous animals and plants appear Asa Gray beak become bees believe birds breeds caudicle cause cells characters climate closely colour common crossed cuckoo degree descendants developed difficulty distinct species disuse divergence domestic animals domestic races doubt effects eggs existence extinct extremely facts favourable females flowers forms Fritz Müller genera genus giraffe gradations greater number groups habits Hence hermaphrodites hive-bee important increase inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ large number larger genera larvæ less males manner Melipona Mivart modified natural selection naturalists nearly nest occasionally offspring organisation organs origin Origin of Species parent perfect period pigeons pollen pollen-grains present preserved prey principle probably produced progenitor quadrupeds rank rarely Red Grouse relation remarked resemble rock-pigeon seeds sexes sexual selection slight stamens striped structure struggle supposed swimbladder tend tendency tion tree variability variations varieties vary widely wings young