On the Origin of Species by Means of Natural Selection, Or, The Preservation of Favoured Races in the Struggle for LifeAppleton, 1898 - 432 páginas |
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Página 50
... theory , that one of two living forms might have descended from the other ; for instance , a horse from a tapir ; and in this case direct intermediate links will have existed between them . But such a case would imply that one form had ...
... theory , that one of two living forms might have descended from the other ; for instance , a horse from a tapir ; and in this case direct intermediate links will have existed between them . But such a case would imply that one form had ...
Página 51
... theory of natural selection all living species have been connected with the parent - species of each genus , by differences not greater than we see between the natural and domestic varieties of the same species at the present day ; and ...
... theory of natural selection all living species have been connected with the parent - species of each genus , by differences not greater than we see between the natural and domestic varieties of the same species at the present day ; and ...
Página 70
... theory have existed , but abrupt , though perhaps slight , changes of form . It is all - important to remember that naturalists have no golden rule by which to distinguish species and varieties ; they grant some little variability to ...
... theory have existed , but abrupt , though perhaps slight , changes of form . It is all - important to remember that naturalists have no golden rule by which to distinguish species and varieties ; they grant some little variability to ...
Página 71
... theory we ought to find . Look again at the later tertiary deposits , which include many shells believed by the majority of natu- ralists to be identical with existing species ; but some excellent naturalists , as Agassiz and Pictet ...
... theory we ought to find . Look again at the later tertiary deposits , which include many shells believed by the majority of natu- ralists to be identical with existing species ; but some excellent naturalists , as Agassiz and Pictet ...
Página 72
... theory ; but to this latter subject I shall return in the following chapter . With animals and plants that propagate rapidly and do not wander much , there is reason to suspect , as we have formerly seen , that their varieties are ...
... theory ; but to this latter subject I shall return in the following chapter . With animals and plants that propagate rapidly and do not wander much , there is reason to suspect , as we have formerly seen , that their varieties are ...
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admit affinity allied species ancient animals appear Archipelago arctic areas become believe birds Cambrian changes characters cies classification climate closely allied common progenitor continent crustaceans degree deposited difficulty distant distinct species domestic doubt embryo eral Europe existing extinct fact faunas fertilised fertility flowers formations formerly forms fossil fresh-water Fritz Müller Gärtner genera genus geological period geological record Glacial period groups of species habits hybrids hybrids produced important individuals inhabitants inherited insects instance intermediate intervals land larvæ less living mammals manner marine Marsupials migration modified descendants mongrels mountains natural selection naturalists nearly occur oceanic islands offspring organisation parent parent-form peculiar perfect pistil plants pollen present probably produced quadrupeds reciprocal crosses regions remains remarked reproductive resemblance rocks rudimentary organs sediment seeds Silurian South America stage stamens sterility structure successive suppose terrestrial tertiary theory tion variations varieties whilst widely different wings