The Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeF. Ungar Publishing Company, 1956 - 134페이지 |
도서 본문에서
13개의 결과 중 1 - 3개
6 페이지
... 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 give one instance : -I crossed some white fantails , which breed very true , with ...
... 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 give one instance : -I crossed some white fantails , which breed very true , with ...
74 페이지
... crossed ; its appearance is often due to incidental factors , such as in- breeding The view commonly enter- tained by naturalists is that species , when inter- crossed , have been special- ly endowed with sterility , in order to prevent ...
... crossed ; its appearance is often due to incidental factors , such as in- breeding The view commonly enter- tained by naturalists is that species , when inter- crossed , have been special- ly endowed with sterility , in order to prevent ...
82 페이지
... crossed are not invariably quite fertile . Thus , the general sterility of crossed species may safely be looked at as not a special endowment . In all other respects there seems to be a general and close similarity in the offspring of ...
... crossed are not invariably quite fertile . Thus , the general sterility of crossed species may safely be looked at as not a special endowment . In all other respects there seems to be a general and close similarity in the offspring of ...
목차
Variation under Domestication | 1 |
Variation under Nature | 12 |
Struggle for Existence | 19 |
저작권 | |
표시되지 않은 섹션 9개
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자주 나오는 단어 및 구문
accumulated adapted affinity allied species animals aphides appear areas become believe birds breeds Cambrian characters CHARLES DARWIN climate closely allied common continent crossed crustaceans cuckoo Darwin degree descended developed difficulty distinct species disuse domestic effects eggs embryo embryology eminently liable existing extermination extinct extremely fact favourable females fertilised fertility flower formations fossil genera genus geological geological period giraffe gradations greater number groups habits Hence hybrids hybrids produced important increase individuals inhabitants inheritance insects instance instincts intercrossing intermediate intervals islands larvae less living males mammals manner Marsupials migration Mivart modification natural selection naturalists nearly nest neuters occasional offspring organisation Origin of Species parent perfect pigeon plants pollen probably produced progenitor pupae quadrupeds rank reciprocal crosses reproductive systems resemblance rock-pigeon rudimentary organs seeds sexual selection slaves slight stage sterility structure struggle swimbladder tend tendency theory of natural tion variability variations varieties vary widely young