The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
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Página vi
... developed in an unusual manner are highly variable ; specific characters more variable than generic : secondary sexual characters variable - Species of the same genus vary in an analogous manner - Reversions to long - lost characters ...
... developed in an unusual manner are highly variable ; specific characters more variable than generic : secondary sexual characters variable - Species of the same genus vary in an analogous manner - Reversions to long - lost characters ...
Página vii
... developed from one and the same source - Reasons for disbelieving in great and abrupt modifications 156 .. CHAPTER VIII . INSTINCT . Instincts comparable with habits , but different in their origin - Instincts graduated - Aphides and ...
... developed from one and the same source - Reasons for disbelieving in great and abrupt modifications 156 .. CHAPTER VIII . INSTINCT . Instincts comparable with habits , but different in their origin - Instincts graduated - Aphides and ...
Página 3
... developed being or into an elaborately con- structed organ ; secondly , the subject of Instinct , or the mental powers of animals ; thirdly , Hybridism , or the infertility of species and the fertility of varieties when intercrossed ...
... developed being or into an elaborately con- structed organ ; secondly , the subject of Instinct , or the mental powers of animals ; thirdly , Hybridism , or the infertility of species and the fertility of varieties when intercrossed ...
Página 15
... develop- ment of the carunculated skin about the head ; and this is accompanied by greatly elongated eyelids , very ... developed crop , which it glories in inflating , may well excite astonishment and even laughter . The turbit has a ...
... develop- ment of the carunculated skin about the head ; and this is accompanied by greatly elongated eyelids , very ... developed crop , which it glories in inflating , may well excite astonishment and even laughter . The turbit has a ...
Página 17
... developed . Moreover , when birds belonging to two or more distinct breeds are crossed , none of which are blue or have any of the above - specified marks , the mongrel offspring are very apt suddenly to acquire these characters . To ...
... developed . Moreover , when birds belonging to two or more distinct breeds are crossed , none of which are blue or have any of the above - specified marks , the mongrel offspring are very apt suddenly to acquire these characters . To ...
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Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young