The Doctrine of Descent and DarwinismD. Appleton and Company, 1875 - Всего страниц: 334 |
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Стр. 28
... sexual organs . On the other hand , hours do not suffice to describe the structure of a bee . Even externally , its body , which possesses so highly complicated a structure , pro- mises a rich development of the interior . The man ...
... sexual organs . On the other hand , hours do not suffice to describe the structure of a bee . Even externally , its body , which possesses so highly complicated a structure , pro- mises a rich development of the interior . The man ...
Стр. 42
... sexual method , and from its eggs proceed Stauridia . The two generations thus alter- nate ; the cross - polype is an intermediate generation in the development of the Medusa , so that the sexual genera- tion never originates directly ...
... sexual method , and from its eggs proceed Stauridia . The two generations thus alter- nate ; the cross - polype is an intermediate generation in the development of the Medusa , so that the sexual genera- tion never originates directly ...
Стр. 43
... sexually mature individuals ; or , according to Haeckel's definition , are endowed with personality . If the tape - worm now comported itself like most other animals , somites would be directly developed from its eggs . But to this ...
... sexually mature individuals ; or , according to Haeckel's definition , are endowed with personality . If the tape - worm now comported itself like most other animals , somites would be directly developed from its eggs . But to this ...
Стр. 44
... sexual generation . In the evolutionary cycles just discussed , there is an alternation of asexual and sexual reproduction ; and before examining some other cases of asexual multi- plication , we must make ourselves acquainted with the ...
... sexual generation . In the evolutionary cycles just discussed , there is an alternation of asexual and sexual reproduction ; and before examining some other cases of asexual multi- plication , we must make ourselves acquainted with the ...
Стр. 45
... sexual element , the sperm , contains , as its peculiar active constituents , the spermatozoa ( fig . 4 s ) , which consist of a pointed , elliptic , or occasionally of a hook - shaped , FIG . 4 . S head , and a thread - like body . As ...
... sexual element , the sperm , contains , as its peculiar active constituents , the spermatozoa ( fig . 4 s ) , which consist of a pointed , elliptic , or occasionally of a hook - shaped , FIG . 4 . S head , and a thread - like body . As ...
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according adaptation already Ammonites Amphibians animal world apes appearance Ascidian become birds brain causes Cetacea character characteristics comparative anatomy complete connection continent Darwin dentition derivation diverge doctrine of Descent Echinoderms embryonic Eocene exhibit external facts families fauna fish formation fossil Ganoids Gastrula genera genus geological Goethe grade gradually groups Haeckel heredity higher horse human hypothesis idea individual infer intermediate forms islands lancelet language larva larvæ likewise linguistic Linnæus lower mammals Marsupials Medusa ment merely metamorphosis modifications morphological mutability natural selection observation Oolite organisms origin peculiar pedigree perfect period phase phenomena placenta plants polypes possess present primordial progenitors races relations remains reproduction reptiles resemblance Rütimeyer says scarcely scientific separate sexual Silurian skull species sponges strata structure systematic terrestrial animals Tertiary theory of selection tion transformation transition true Ungulata Ungulates varieties vegetal vertebral column Vertebrata vertebrate animals whole
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Стр. 162 - There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.18 Darwin always knew that his views would be controversial. A few days before The Origin of Species appeared, Darwin wrote, in a letter to Wallace, 'God knows what...
Стр. 160 - I had not formerly sufficiently considered the existence of many structures which appear to be, as far as we can judge, neither beneficial nor injurious ; and this I believe to be one of the greatest oversights as yet detected in my work.
Стр. 160 - Na'geli on plants, and the remarks by various authors with respect to animals, more especially those recently made by Professor Broca, that in the earlier editions of my Origin of Species I perhaps attributed too much to the action of natural selection or the survival of the fittest.