Nature Sketches in Temperate America: A Series of Sketches and Popular Account of Insects, Birds, and Plants, Treated from Some Aspects of Their Evolution and Ecological RelationsA. C. McClurg, 1911 - 451 páginas |
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Página 7
... frequent the same districts , require the same food , and are exposed to the same dangers . " He further maintained that in all nature we see a strong tendency to variation . Now if any organic being varies even in a slight degree owing ...
... frequent the same districts , require the same food , and are exposed to the same dangers . " He further maintained that in all nature we see a strong tendency to variation . Now if any organic being varies even in a slight degree owing ...
Página 39
... frequently attached to the claws of insects and rarely to the hairs and mouth parts , in the allied species of milkweed , A. verticillata , the pollinia are usually attached to the hairs of insect visitors . The peculiar structure of ...
... frequently attached to the claws of insects and rarely to the hairs and mouth parts , in the allied species of milkweed , A. verticillata , the pollinia are usually attached to the hairs of insect visitors . The peculiar structure of ...
Página 41
... frequent these blossoms are not destroyed in such numbers . To the butterflies , the floral spread presents an enticing playground , as well as a place to banquet . And even the weak flies and small bugs move about among the bright ...
... frequent these blossoms are not destroyed in such numbers . To the butterflies , the floral spread presents an enticing playground , as well as a place to banquet . And even the weak flies and small bugs move about among the bright ...
Página 44
... frequent flowers often bear strictly specialized mouth parts in adaptation to their mode of life , the humming - bird's head and body appear to have been changed in accordance with his habits . Aside from the bill , which is modified in ...
... frequent flowers often bear strictly specialized mouth parts in adaptation to their mode of life , the humming - bird's head and body appear to have been changed in accordance with his habits . Aside from the bill , which is modified in ...
Página 47
... frequently matted together by the sticky secretion referred to , gathered from the flowers while the birds are in search of food . Attached to the many pointed and flattened surfaces are seen pollen grains of many kinds , chiefly of ...
... frequently matted together by the sticky secretion referred to , gathered from the flowers while the birds are in search of food . Attached to the many pointed and flattened surfaces are seen pollen grains of many kinds , chiefly of ...
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Términos y frases comunes
abdomen adaptation adult ambush bug animals antennæ appear August Baltimore oriole bark bees beetle birds blossoms body border brown bumblebee burrow butterfly caterpillar color common cone-head Cricket Darwin Datana dunes eggs evolution feeding feet female Field Cricket fields flies flowers forest frequently genus goldenrod grass green ground Grouse Locust habitat habits hatch herbage inches individuals Initial drawing insect visitors insects July katydid laid landscape larva larvæ leaf leaves legs light living Locust Melanoplus male margin meadow grasshopper milkweed mimicry mole cricket moth natural selection nest night nymph observations Orchelimum Orthoptera ovipositor pair parasitic pastures plants plate photographic illustration pollen pollinia ponds prey protective resemblance pupa sand locust sandy seen showing shown shrubs side species spider spots stem stridulating striped surface thickets tion toad tree twig upper variations visiting walking-stick wasp weed wild wings witch-hazel woods yellow young
Pasajes populares
Página 7 - I may be allowed to personify the natural preservation or survival of the fittest, cares nothing for appearances, except in so far as they are useful to any being. She can act on every internal organ, on every shade of constitutional difference, on the whole machinery of life. Man selects only for his own good : Nature only for that of the being which she tends.
Página 17 - If it could be proved that any part of the structure of any one species had been formed for the exclusive good of another species, it would annihilate my theory, for such could not have been produced through natural selection.
Página 9 - ... nests. An action, which we ourselves require experience to enable us to perform, when performed by an animal, more especially by a very young one, without experience, and when performed by many individuals in the same way, without their knowing for what purpose it is performed, is usually said to be instinctive.
Página 5 - There is no exception to the rule that every organic being naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair. Even slow-breeding man has doubled in twenty-five years, and at this rate, in less than a thousand years, there would literally not be standing room for his progeny.
Página 65 - In the tropics there are thousands of species of insects which rest during the day clinging to the bark of dead or fallen trees; and the greater portion of these are delicately mottled with gray and brown tints, which though symmetrically disposed and infinitely varied, yet blend so completely with the usual colours of the bark, that at two or three feet distance they are quite undistinguishable.
Página 5 - What a struggle between the several kinds of trees must here have gone on during long centuries, each annually scattering its seeds by the thousand ; what war between insect and insect — between insects, snails, and other animals with birds and beasts of prey — all striving to increase, and all feeding on each other or on the trees or their seeds and seedlings, or on the other plants which first clothed the ground and thus checked the growth of the trees...
Página 332 - ... which, with the aid of the palpi, guide the point to that portion of the leaf prepared to receive it. After gentle, but repeated efforts, the point of the instrument is finally inserted between the tissues of the leaf, and gradually pushed in to more than half its length. As soon as the cavity is formed, the egg is extruded, and passed slowly between the semi-transparent blades of the ovipositor. As the egg leaves the ovipositor the latter is gradually withdrawn, while the egg remains in the...
Página 7 - Under nature, the slightest difference of structure or constitution may well turn the nicely balanced scale in the struggle for life, and so be preserved. How fleeting are the wishes and efforts of man! how short his time! and consequently how poor will his products be, compared with those accumulated by nature during whole geological periods. Can we wonder, then, that nature's productions should be far "truer...
Página 332 - This leaf is then grasped by the front feet and held in a vertical position, while the edge is slightly gnawed or pared off by the jaws to facilitate the entrance of the point of the ovipositor. When this is done the abdomen is curved under and brought forward, and the ovipositor is seized on its...