Animal Life: A First Book of ZoölogyD. Appleton, 1900 - Всего страниц: 329 |
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Стр. v
... reasons for the varied structure and habits of animals . To understand how naturally and inevitably all animal form , habit , and life are adapted to the varied circumstances and conditions of animal existence should be the motive of ...
... reasons for the varied structure and habits of animals . To understand how naturally and inevitably all animal form , habit , and life are adapted to the varied circumstances and conditions of animal existence should be the motive of ...
Стр. ix
... REASON . Irritability , 240. - Nerve cells and fibers , 240. - The brain or sensorium , 241. - Reflex action , 241. - Instinct , 242. - Classifica- tion of instincts , 243. - Feeding , 244. - Self - defense , 245. - Play , 247 ...
... REASON . Irritability , 240. - Nerve cells and fibers , 240. - The brain or sensorium , 241. - Reflex action , 241. - Instinct , 242. - Classifica- tion of instincts , 243. - Feeding , 244. - Self - defense , 245. - Play , 247 ...
Стр. 61
... reason for this great difference in fertility among different animals , we may find a promis- ing clew by attending to the duration of life of animals , and to the amount of care for the young exercised by the parents . We find it to be ...
... reason for this great difference in fertility among different animals , we may find a promis- ing clew by attending to the duration of life of animals , and to the amount of care for the young exercised by the parents . We find it to be ...
Стр. 102
... reason or reasons are wholly known , yet the probability is strong that the duration of life is closely connected with , or dependent upon , the conditions attending the production of offspring . It is not sufficient , as we have ...
... reason or reasons are wholly known , yet the probability is strong that the duration of life is closely connected with , or dependent upon , the conditions attending the production of offspring . It is not sufficient , as we have ...
Стр. 109
... reason they do not notice it . The animals that live in water , however , sustain a much greater pres- sure , this pressure increasing with the depth . Certain ocean fishes live habitually at great depths , as two to five miles , where ...
... reason they do not notice it . The animals that live in water , however , sustain a much greater pres- sure , this pressure increasing with the depth . Certain ocean fishes live habitually at great depths , as two to five miles , where ...
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adaptation adult alimentary canal Amaba ants artificial selection becomes bees beetles birds body wall breathing butterfly called cavity chitin CLASS colony color complex animals composed conjugation crab differentiation digestion divide division of labor ectoderm egg cells embryo existence feed female fertilized fish flagella free-swimming function gastrula Globigerinæ habits hatched higher animals honey-bee Hydra inclosed increase insects instinct intestine jelly-fishes kinds of animals larva larvæ layer live male mals mammals many-celled animals mass medusæ metamorphosis naturalists nerve nest nucleus ocean one-celled organs outer oxygen Pandorina papillæ Paramecium parasites parent perform plant-lice plants polyp prey primitive processes produced protoplasm Protozoa pseudopods pupa queen Radiolaria reproductive cells Sacculina sea-anemone shell simple simplest animals single cell special sense species sperm cells spherical sponge stage structure substance surface swimming tentacles tion tissues vertebrates Volvox Vorticella wings workers worms young
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Стр. 115 - 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.
Стр. 215 - He cannot be mistaken for any other, and his flaming vest and blue stockings show that he does not court concealment. He is very abundant in the damp woods, and I was convinced he was uneatable so soon as I made his acquaintance and saw the happy sense of security with which he hopped about. I took a few specimens home with me, and tried my fowls and ducks with them ; but none would touch them. At last, by throwing down pieces of meat, for which there was a great competition amongst them, I managed...
Стр. 20 - ... inhabitants of the water has followed a roundabout path from the surface to the bottom and then back into the water. When this fact is seen in all its bearings and its full significance is grasped, it is certainly one of the most notable and instructive features of evolution. The food-supply of marine animals consists of a few species of microscopic organisms which are inexhaustible and the only source of food for all the inhabitants of the ocean.
Стр. 116 - The elephant is reckoned the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase; it will be safest to assume that it begins breeding when thirty years old, and goes on breeding till ninety years old, bringing forth six young in the interval, and surviving till one hundred years old ; if this be so, after a period of from 740 to 750 years there would be nearly nineteen million elephants alive, descended from the first pair.