On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeHeritage Press, 1963 - 470페이지 |
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252 페이지
... hybrids produced from this cross ; that the fertility of hybrids is not related to the degree in which they resemble in external appearance either parent ; and lastly , that the facility of making a first cross between any two species ...
... hybrids produced from this cross ; that the fertility of hybrids is not related to the degree in which they resemble in external appearance either parent ; and lastly , that the facility of making a first cross between any two species ...
258 페이지
... produce sterile hybrids . On the other hand , one species in a group will sometimes resist great changes of conditions with unimpaired fertility ; and certain species in a group will produce unusually fertile hybrids . No one can tell ...
... produce sterile hybrids . On the other hand , one species in a group will sometimes resist great changes of conditions with unimpaired fertility ; and certain species in a group will produce unusually fertile hybrids . No one can tell ...
262 페이지
... hybrids when crossed inter se . If , on the other hand , a hybrid is crossed with either pure parent - species , the ... produced within the limits of the same species by the improper union of certain forms , whilst ordinary hybrids are ...
... hybrids when crossed inter se . If , on the other hand , a hybrid is crossed with either pure parent - species , the ... produced within the limits of the same species by the improper union of certain forms , whilst ordinary hybrids are ...
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자주 나오는 단어 및 구문
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters cirripedes climate closely allied colour common progenitor continuous crossed crustaceans degree developed difficulty distinct species divergence doubt effects eggs embryo existing exterminated extinct extremely fact favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period gradations greater number habits Hence hybrids hybrids produced 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 offspring organisation organs parent peculiar perfect pigeons pistil plants pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection slight South America stamens sterility structure successive supposed swimbladder theory variability variations varieties vary whilst whole widely different wings young