The Study of Animal LifeSribner, 1917 - 477 páginas |
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Página 36
... selection ; for those communities which included the greatest number of the most sympathetic members would flourish best , and rear the greatest number of offspring . " 66 Thus We are dwelling on this because of the very unfor- tunate ...
... selection ; for those communities which included the greatest number of the most sympathetic members would flourish best , and rear the greatest number of offspring . " 66 Thus We are dwelling on this because of the very unfor- tunate ...
Página 42
... selection or survival of the fittest , as the struggle between tiger and tiger , between bison and bison , between snake and snake , between antelope and antelope . Homo homini lupus , says the old proverb , and so , we may add , in a ...
... selection or survival of the fittest , as the struggle between tiger and tiger , between bison and bison , between snake and snake , between antelope and antelope . Homo homini lupus , says the old proverb , and so , we may add , in a ...
Página 53
... selection would foster it , favouring with success those variations which were best adapted , and eliminating those which were conspicuous . 5. Variable Colouring . Some animals , such as the ptarmigan and the mountain - hare , become ...
... selection would foster it , favouring with success those variations which were best adapted , and eliminating those which were conspicuous . 5. Variable Colouring . Some animals , such as the ptarmigan and the mountain - hare , become ...
Página 54
... selection , and that its limits were in the same way more or less defined in adaptation to the most frequent habitat of the larvæ before and during pupation . 6. Rapid Change of Colour . - For ages the chamæleon has been famous for its ...
... selection , and that its limits were in the same way more or less defined in adaptation to the most frequent habitat of the larvæ before and during pupation . 6. Rapid Change of Colour . - For ages the chamæleon has been famous for its ...
Página 59
... selection . 8. Warning Colours . While many animals are con- cealed by their colouring , others are made the more conspicuous . But , as the latter are often unpalatable or dangerous , Wallace suggested that the colours were Off FIG ...
... selection . 8. Warning Colours . While many animals are con- cealed by their colouring , others are made the more conspicuous . But , as the latter are often unpalatable or dangerous , Wallace suggested that the colours were Off FIG ...
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Palavras e frases frequentes
activity adaptations adult amoeboid Amphibians ants ARTHUR THOMSON become bees begin behaviour Biology birds body brain buds called cells centrosome changes characteristic characters chromosomes cilia colony colour complex crab creatures crustaceans cuttlefish Darwin Echinoderms egg-cell eggs embryo environment evolution Evolution of Sex eyes fact female fertilised fishes flowers food-canal forms freshwater frog function germ-cells gills grow habit heredity higher animals hydroid illustration individual influence Infusorians inheritance insects instinctive kind lancelet larva larvæ life-history living matter London male mammals mates molluscs mouth muscles Natural History naturalists nervous system nest notochord nucleus nurture nutritive offspring organism ovum pairs parasitic parents physiological plants Prof Protozoa RAY LANKESTER reproductive reptiles result Rotifers sea-anemones shells simplest skin sometimes species spermatozoon spiders sponges starfish structure struggle for existence surface surroundings T. H. MORGAN theory tion tissues trans Vertebrates vols wings worms young Zoology
Passagens conhecidas
Página 323 - Tis but an hour ago since it was nine, And after one hour more 'twill be eleven ; And so, from hour to hour, we ripe and ripe, And then, from hour to hour, we rot and rot ; And thereby hangs a tale.
Página 196 - I believe a leaf of grass is no less than the journey-work of the stars, And the pismire is equally perfect, and a grain of sand, and the egg of the wren, And the tree-toad is a...
Página 159 - In no case may we interpret an action as the outcome of the exercise of a higher psychical faculty, if it can be interpreted as the outcome of the exercise of one which stands lower in the psychological scale.
Página 196 - And the pismire is equally perfect, and a grain of sand, and the egg of the wren, And the tree-toad is a chef-d'oeuvre for the highest, And the running blackberry would adorn the parlors of heaven, And the narrowest hinge in my hand puts to scorn all machinery, And the cow crunching with depressed head surpasses any statue, And a mouse is miracle enough to stagger sextillions of infidels.
Página 46 - Are God and Nature then at strife, That Nature lends such evil dreams So careful of the type she seems, So careless of the single life...
Página 284 - It scarcely breathes with its one lung (the other shrivelled and abortive) ; it is passive to the sun and shade, and is cold or hot like a stone ; yet " it can outclimb the monkey, outswim the fish, outleap the zebra, outwrestle the athlete, and crush the tiger.
Página 369 - germ-plasm,' and have assumed that it possesses a highly complex structure, conferring upon it the power of developing into a complex organism. I have attempted to explain heredity by supposing that in each ontogeny, a part of the specific germ-plasm contained in the parent egg-cell is not used up in the construction of the body of the offspring, but is reserved unchanged for the formation of the germ-cells of the following generation.
Página 417 - Fifthly, from their first rudiment, or primordium, to the termination of their lives, all animals undergo perpetual transformations, which are in part produced by their own exertions in consequence of their desires and aversions, of their pleasures and pains, or of irritations, or of associations; and many of these acquired forms or propensities are transmitted to their posterity.
Página 36 - I should premise that I use the term Struggle for Existence in a large and metaphorical sense, including dependence of one being on another, and including (which is more important) not only the life of the individual, but success in leaving progeny.
Página 417 - As air and water are supplied to animals in sufficient profusion, the three great objects of desire, which have changed the forms of many animals by their exertions to gratify them, are those of lust, hunger and security.