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absorbed active adapted alimentary canal animals and plants appear arise attached become begin blood body bones called carbon carried cavity cells changes characters chemical Class closely common contain developed digestive divides division energy evident example fact fertilization Figure flower follows force frog functions gametophyte germ green growing growth heart higher individual intestine known layer leaves liquid living machine mass material means method microscopic minute motion mouth muscles mycelium nature nerve nucleus occurs opening organisms original oxygen passes possesses present produced protoplasm relation remain reproduction result root seen separate sexual reproduction shape shown side similar simple single sometimes species sperm spores stage starch stem structure substance surface theory tion tissues true tube union unite usually variations various vessels walls whole
Page 353 - ... in the long run, to win in the contest. Hence the " fittest " in the long run will survive, while those less fitted to exist will be exterminated. " 5. Heredity. By the laws of heredity, individuals transmit to their offspring their own characters. Hence if one individual survives the struggle for existence by virtue of some special characteristic, it will transmit this characteristic to its offspring. The offspring will inherit it, and in the course of a few generations the only individuals...
Page 353 - 1. Overproduction. All animals and plants tend to multiply more rapidly than it is possible for them to continue to exist. More offspring are produced by even the slowest breeding animals and plants than can possibly find sustenance in the world. " 2. Struggle for existence. As a result of overproduction, the individuals that are born are engaged in a constant struggle with each other for the opportunity to live. This struggle is sometimes an active, sometimes a passive one; and sometimes it is...
Page 24 - Observations upon the generation, composition, and decomposition of animals and vegetable substances, London, 1749 ; Notes sur les Nouvelles decouvertes de Spallanzani, Paris, 1768.
Page iii - List price, 50 cents; mailing price, 55 cents THIS work is intended to serve as an introduction to the study of algebra, and is adapted to the needs of the seventh or eighth school year. It is arranged in harmony with the leading courses of study that include algebra in the curriculum of the grades. The relation of algebra to arithmetic is emphasized, the subject is treated topically, and each important point...
Page 372 - ... reader in becoming familiar with the technical terms applied to the organs or parts of the flower which it is desirable to understand, and by means of which he will soon learn to distinguish the different species more readily. In giving the scientific names, the first word that occurs in parenthesis is the name of the genus ; the second, that of the species ; as, for instance, in Timothy (Phleum pratense), Phleum is the generic name, pratense the specific.
Page 188 - This sinus opens into the right auricle, which thus receives all the blood which flows back to the heart from all parts of the body, except the lungs. The blood from the lungs empties into the left auricle by two small veins, one from each lung; Fig.
Page 375 - The classification accepted by science is ever undergoing changes, as a more complete knowledge of relations is obtained, and the classification accepted to-day is different in many respects from that adopted a generation ago. In turn, the classification used to-day will doubtless be modified by future study, until it becomes practically perfect.
Page 377 - PLATYHELMINTHES: flat, unsegmented worms. Class I. Cestoda: the tapeworms. Class II. Trematoda: the flukes. Class III. Turbellaria: the planarians. Phylum V. NEMATHELMINTHES : round, unsegmented worms: round worms, threadworms. Phylum VI. MOLLUSCOIDEA. Class I. Polyzoa: sea-mats, corallines. Class II. Brachiopoda: lamp-shells. Phylum VII.