On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeD. Appleton, 1909 - 430 páginas |
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Página 10
... known fossiliferous strata 245 CHAPTER X ON THE GEOLOGICAL SUCCESSION OF ORGANIC BEINGS On the slow and successive appearance of new species - On their different rates of change - Species once lost do not reappear- Groups of species ...
... known fossiliferous strata 245 CHAPTER X ON THE GEOLOGICAL SUCCESSION OF ORGANIC BEINGS On the slow and successive appearance of new species - On their different rates of change - Species once lost do not reappear- Groups of species ...
Página 16
... known laws of variation and of corre- lation of growth . In the four succeeding chapters , the most apparent and gravest difficulties on the theory will be given : namely , first , the difficulties of transitions , or in understanding ...
... known laws of variation and of corre- lation of growth . In the four succeeding chapters , the most apparent and gravest difficulties on the theory will be given : namely , first , the difficulties of transitions , or in understanding ...
Página 24
... known to appear at the corresponding caterpillar or cocoon stage . But hereditary diseases and some other facts make me believe that the rule has a wider extension , and that when there is no apparent reason why a peculiarity should ...
... known to appear at the corresponding caterpillar or cocoon stage . But hereditary diseases and some other facts make me believe that the rule has a wider extension , and that when there is no apparent reason why a peculiarity should ...
Página 28
... known facts , come to the conclusion that several wild species of Canidæ have been tamed , and that their blood , more or less mingled , flows in the veins of our many domestic breeds . In regard to sheep and goats I can form no opinion ...
... known facts , come to the conclusion that several wild species of Canidæ have been tamed , and that their blood , more or less mingled , flows in the veins of our many domestic breeds . In regard to sheep and goats I can form no opinion ...
Página 32
... known ; and these have not any of the characters of the domestic breeds . Hence the supposed aboriginal stocks must either still exist in the countries where they were originally domesti- cated , and yet be unknown to ornithologists ...
... known ; and these have not any of the characters of the domestic breeds . Hence the supposed aboriginal stocks must either still exist in the countries where they were originally domesti- cated , and yet be unknown to ornithologists ...
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Términos y frases comunes
accumulated adapted affinities allied species America analogous ancient animals appear archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour continuous crossed crustaceans degree difficulty distinct species divergence domestic doubt embryo endemic existing exterminated extinct extremely facts favourable fertilised fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hybrids hybrids produced important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate larvæ laws less living males mammals manner migration modification modified descendants natural selection naturalists nearly nest occasionally offspring organic organisation origin of species perfect pigeons plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary seeds sexual sexual selection Silurian slight sometimes South America sterility structure struggle successive supposed swimbladder tend theory variability variations varieties vary whole widely