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actions activity adaptation aggregate alterations amounts animals appears arise arrangement assume atoms become body called cause cells certain changes chemical combination common comparatively complex compounds conclusion consider considerable constituting contained continuous contrasts correspondence creatures definite differentiation direct displayed distinct divergences effects environment equilibrium established evidence evolution exist external extreme facts flower follows forces forms functions further germ give given going greater groups grow growth habitually heat Hence heterogeneity higher hypothesis implies incident increase individuals kind less limit living manifest marked mass matter means modes modifications molecular motion moving natural needful observed offspring organisms original parent passing phenomena physiological units plants present produced races relations respect result separate shown similarly special creations species structure substances successive throughout tion tissues truth types units unlike variations varieties various whole
Page 74 - is a definite combination of heterogeneous changes, both simultaneous and successive, in correspondence with external coexistences and sequences.
Page 492 - Their implications are no more materialistic than they are spiritualistic; and no more spiritualistic than they are materialistic.
Page 183 - There seems no alternative but to suppose that the chemical units combine into units immensely more complex than themselves, complex as they are; and that in each organism, the physiological -units produced by this further compounding of highly compound atoms, have a more or less distinctive character. We must conclude that in each case, some slight difference of composition . in these units, leading to some slight difference in their mutual play of forces, produces a difference in the form which...
Page 175 - It is a corollary from that primordial truth which, as we have seen, underlies all other truths, that whatever amount of power an organism expends in any shape is the correlate and equivalent of a power that was taken into it from without.
Page 61 - Life is a series of definite and successive changes, both of structure and composition, which take place within an individual without destroying its identity.
Page 247 - Kentucky, are blind. In some of the crabs the foot-stalk for the eye remains, though the eye is gone ; — the stand for the telescope is there, though the telescope with its glasses has been lost. As it is difficult to imagine that eyes, though useless, could be in any way injurious to animals living in darkness, their loss may be attributed to disuse.
Page 370 - Some of the cases of rudimentary organs are extremely curious; for instance, the presence of teeth in foetal whales, which when grown up have not a tooth in their heads; and the presence of teeth, which never cut through the gums, in the upper jaws of our unborn calves.
Page 445 - This survival of the fittest which I have here sought to express in mechanical terms, is that which Mr. Darwin has called " natural selection, or the preservation of favoured races in the struggle for life.