Contributions to the Theory of Natural Selection: A Series of EssaysMacmillan and Company, 1870 - 384 pages |
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Page 28
... Existence . The life of wild animals is a struggle for exist- ence . The full exertion of all their faculties and all their energies is required to preserve their own existence and provide for that of their infant off- spring . The ...
... Existence . The life of wild animals is a struggle for exist- ence . The full exertion of all their faculties and all their energies is required to preserve their own existence and provide for that of their infant off- spring . The ...
Page 32
... proportion . The numbers that die annually must be immense ; and as the individual existence of each animal depends upon itself , those that die must be the weakest the very young , the aged , and 32 ON THE TENDENCY OF VARIETIES TO DEPART.
... proportion . The numbers that die annually must be immense ; and as the individual existence of each animal depends upon itself , those that die must be the weakest the very young , the aged , and 32 ON THE TENDENCY OF VARIETIES TO DEPART.
Page 33
... existence can only be the most perfect in health and vigour— those who are best able to obtain food regularly , and avoid their numerous enemies . It is , as we com- menced by remarking , " a struggle for existence , " in which the ...
... existence can only be the most perfect in health and vigour— those who are best able to obtain food regularly , and avoid their numerous enemies . It is , as we com- menced by remarking , " a struggle for existence , " in which the ...
Page 34
... existence under all the varying circumstances by which it is surrounded , we might be able even to calculate the proportionate abundance of individuals which is the necessary result . If now we have succeeded in establishing these two ...
... existence under all the varying circumstances by which it is surrounded , we might be able even to calculate the proportionate abundance of individuals which is the necessary result . If now we have succeeded in establishing these two ...
Page 35
... existence . An antelope with shorter or weaker legs must necessarily suffer more from the attacks of the feline carnivora ; the passenger pigeon with less powerful wings would sooner or later be affected in its powers of procuring a ...
... existence . An antelope with shorter or weaker legs must necessarily suffer more from the attacks of the feline carnivora ; the passenger pigeon with less powerful wings would sooner or later be affected in its powers of procuring a ...
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Contributions to the Theory of Natural Selection: A Series of Essays ... Alfred Russel Wallace No preview available - 2018 |
Contributions to the Theory of Natural Selection: A Series of Essays Alfred Russel Wallace No preview available - 2016 |
Common terms and phrases
abundant action adapted affinity alike Amboyna anal valves animals antennæ archipelago beauty become believe birds Borneo brilliant build butterflies causes Celebes characters closely allied species common concealed consider curious Danaidæ Darwin dimorphism Diphilus distinct species eggs equally evidence exactly example exhibit existence extinct facts faculties favourable female birds flight flowers genera genus groups Guinea habits Heliconidæ hole imitation India individuals inhabiting insects instinct islands Java larvæ laws Lepidoptera less Malayan male materials mimicked mimicry mode modifications Moluccas moths natural selection nectary never nidification observation occur organic Origin of Species Ormenus Ornithoptera Pammon Papilio Papilio Ulysses Papilionidæ peculiar perfect phenomena Polydorus possess present probably proboscis produced protection races reason region remarkable render resemble savage sexes sexual selection shown specimens structure Sumatra supposed tail theory of natural Theseus tints tion trees tropical variation varied varieties whole wings
Popular passages
Page 359 - ... the passage from the current to the needle, if not demonstrable, is thinkable, and that we entertain no doubt as to the final mechanical solution of the problem. But the passage from the physics of the brain to the corresponding facts of consciousness is unthinkable. Granted that a definite thought, and a definite molecular action in the brain occur simultaneously ; we do not possess the intellectual organ, nor apparently any rudiment of the organ, which would enable us to pass, by a process...
Page 366 - WILL, while we have no knowledge of any other primary cause of force, it does not seem an improbable conclusion that all force may be will-force; and thus, that the whole universe is not merely dependent on, but actually is, the WILL of higher intelligences or of one Supreme Intelligence.
Page 357 - A superior intelligence has guided the development of man in a definite direction and for a special purpose, just as man guides the development of many animal and vegetable forms...
Page 23 - Every species has come into existence coincident both in time and space with a preexisting closely allied species," Connects together and renders intelligible a vast number of independent and hitherto unexplained facts.
Page 59 - The little tails of the hind wing touch the branch, and form a perfect stalk to the leaf, which is supported in its place by the claws of the middle pair of feet, which are slender and inconspicuous. The irregular outline of the wings gives exactly the perspective effect of a shrivelled leaf. We thus have size, colour, form, markings, and habits, all combining together to produce a disguise which may be said to be absolutely perfect ; and the protection which it affords is sufficiently indicated...
Page 24 - One of the strongest arguments which have been adduced to prove the original and permanent distinctness of species is, that varieties produced in a state of domesticity are more or less unstable, and often have a tendency, if left to themselves, to return to the normal form of the parent species; and this instability is considered to be a distinctive peculiarity of all varieties, even of those occurring among wild animals in a state of nature, and to constitute a provision for preserving unchanged...
Page 354 - Natural Selection could only have endowed the savage with a brain a little superior to that of an ape, whereas he actually possesses one but very little inferior to that of the average members of our learned societies.
Page 39 - The powerful retractile talons of the falcon- and the cat-tribes have not been produced or increased by the volition of those animals; but among the different varieties which occurred in the earlier and less highly organized forms of these groups, those always survive longest which had the greatest facilities for seizing their prey.
Page 359 - ... the other. They appear together, but we do not know why. Were our minds and senses so expanded, strengthened, and illuminated as to enable us to see and feel the very molecules of the brain ; were we capable of following all their motions, all their groupings, all their electric discharges, if such there be ; and were we intimately acquainted with the corresponding states of thought and feeling, we should be as far as ever from the solution of the problem, " How are these physical processes connected...
Page 25 - ... even identical with those of domestic animals, and are governed by the same laws as regards their permanence or further variation. But it is the object of the present paper to show that this assumption is altogether false, that there is a general principle in nature which will cause many varieties to survive the parent species, and to give rise to successive variations departing further and further from the original type, and which also produces, in domesticated animals, the tendency of varieties...