Animal Life: A First Book of ZoölogyD. Appleton, 1900 - Всего страниц: 329 |
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Стр. 2
... whole body of any one of the simplest animals or Protozoa is composed for the animal's whole lifetime of but a single cell . The bodies of all other animals are composed of many cells . The cell may be called the unit of animal ( or ...
... whole body of any one of the simplest animals or Protozoa is composed for the animal's whole lifetime of but a single cell . The bodies of all other animals are composed of many cells . The cell may be called the unit of animal ( or ...
Стр. 3
... whole . The protoplasm , which is the essential substance of the cell and hence of the whole animal body , is a substance of a very complex chemical and physical constitution . Its. THE LIFE OF THE SIMPLEST ANIMALS 3.
... whole . The protoplasm , which is the essential substance of the cell and hence of the whole animal body , is a substance of a very complex chemical and physical constitution . Its. THE LIFE OF THE SIMPLEST ANIMALS 3.
Стр. 9
... whole body was used in performing these functions , and the young are simply two parts of the parent's body . But if there be any doubt about the matter , observation of the behavior of the young or new Amaba will soon remove it . Each ...
... whole body was used in performing these functions , and the young are simply two parts of the parent's body . But if there be any doubt about the matter , observation of the behavior of the young or new Amaba will soon remove it . Each ...
Стр. 21
... whole body of the simplest animals is a single spherical cell , and that every one of the higher animals , however complex it may become by growth and development , begins life as a single spherical cell . 12. The primitive but ...
... whole body of the simplest animals is a single spherical cell , and that every one of the higher animals , however complex it may become by growth and development , begins life as a single spherical cell . 12. The primitive but ...
Стр. 22
... whole body mass takes part in the process of repro- duction . Only very small organisms can live in this simplest way . So all of the Protozoa are minute . When the only part of the body which can absorb oxygen is the simple external ...
... whole body mass takes part in the process of repro- duction . Only very small organisms can live in this simplest way . So all of the Protozoa are minute . When the only part of the body which can absorb oxygen is the simple external ...
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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.