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adaptive admit allied animal kingdom appears argument argument from ignorance artificial selection beauty become birds bones cells chapter characters chromatin classification colour consideration constitute continuity correlation course Darwin Darwinian degree difficulty digitigrade distinct division Drawn egg-cell evidence in favour explain fact faunas fish formation forms fossils function furnished Gastrula genera hand hypothesis importance individual insects instance instincts karyokinesis kind Lastly less male mammalian mammals matter Metazoa modification natural affinity natural causes natural selection naturalists nucleus objections observed occur organic evolution organic nature Origin of Species ovum peculiar species phenomena plantigrade polar bodies present principle Prof pronuclei Protozoa purpose question reason regard remarkable resemblance sexual selection special creation spermatozoon stages structure struggle for existence supposed tail terrestrial theory of descent theory of evolution theory of natural theory of special tion variations Vertebrata vertebrated Wallace whole
Page 225 - stamp of the American continent. There are twenty-six land birds ; of these, twenty-one, or perhaps twenty-three, are ranked as distinct species, and would commonly be assumed to have been here created ; yet the close affinity of most of these birds to American species is manifest in every character, in their habits, gestures, and tones of voice.
Page 427 - would often long remain confined to some one region ; but that, when this adaptation had once been effected, and a few species had thus acquired a great advantage over other organisms, a comparatively short time would be necessary to produce many divergent forms, which would spread rapidly and widely throughout the world.
Page 427 - and, in the succeeding formation, such groups of species will appear as if suddenly created. I may here recall a remark formerly made, namely, that it might require a long succession of ages, to adapt an organism to some new and peculiar line of life, for instance, to fly through the air ; and consequently that the transitional
Page 79 - when about an inch in length, " The great toe is shorter than the others ; and, instead of being parallel to them, is projected at an angle from the side of the foot, thus corresponding with the permanent condition of this part in the Quadrumana 1
Page 432 - The total absence of any trace of fossils has inclined many geologists to attribute the origin of the most ancient strata to an azoic period, or one antecedent to the existence of organic beings. Admitting, they say, the obliteration, in some cases, of fossils by plutonic action, we might still expect that traces of them would
Page 420 - we probably take a quite erroneous view when we assume that sediment is being deposited over nearly the whole bed of the sea, at a rate sufficiently quick to embed and preserve fossil remains. Throughout an enormously large proportion of the ocean, the bright blue tint of the
Page 256 - Not only is the doctrine of the transmutation of species in itself disproved by the best physiological reasonings, but the additional assumptions which are requisite to enable its advocates to apply it to the explanation of the geological and other phenomena of the earth, are altogether gratuitous and fantastical
Page 438 - If we compare the present Alpine plants and animals of the several great European mountain-ranges one with another, though many of the species remain identically the same, some exist as varieties, some as doubtful forms or sub-species, and some as distinct yet closely allied species representing each other on
Page 420 - their preservation, far better than pages of detail. Nor is their rarity surprising, when we remember how large a proportion of the bones of tertiary mammals have been discovered either in caves or in lacustrine deposits; and that not a cave or true lacustrine bed is known belonging to the age of our secondary or palaeozoic formations.