The American Naturalist, Volumen53Essex Institute, 1919 |
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Términos y frases comunes
adaptive albino aleurone AMERICAN NATURALIST ancestors animals appear Apterygota arthropods Articles and Discussion behavior Biological birds blossoms branchiopods breeding carmine cells cent changes character color cross crossing-over Crustacea Darwin direction Echeneis egg-weight eggs endosperm evidence evolution experiments F₂ fact factors females fertilization fish forms fundulus gametes Gärtner genetic germ plasm gerrids habitat heads heterozygous homozygous hull-less hulled kernels hybrid individuals Inheritance insects intermediate isopods larvæ maize male Mammoth mated means Mendelian ments nature non-yellow normal observed occur offspring Onchidium organism ostrich parent parthenogenetically percentage of hulled Phrynosoma pigmentation Pink pink-eyed plants Plecoptera pool present produced Professor progeny race ratio regard relation remiges Remora responses Science seeds selection Shorter Articles species Spirogyra sucking-fish surface Symphyla TABLE Tanaidacea temperature tion trilobites turtle variation varieties W. E. CASTLE W. J. Crozier water-striders yellow Yybb zygospore
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Página 249 - The next care to be taken, in respect of the senses, is a supplying of their infirmities with instruments, and, as it were, the adding of artificial organs to the natural.
Página 258 - Death hindred him) having but a light Body to carry, and a great deal of Spirits and Activity, especially in his youth. He was of an active, restless, indefatigable Genius, even almost to the last, and always slept little to his Death, seldom going to Sleep till two, three, or four o'clock in the Morning and seldomer to Bed, oftener continuing his Studies all Night, and taking a short Nap in the Day. His temper was Melancholy, Mistrustful, and Jealous, which more increas'd -upon him with his years.
Página 506 - 04, p. 56) defines the theorem of Le Chatelier as follows : // a system in equilibrium is subjected to a constraint by which the equilibrium is shifted, a reaction takes place which opposes the constraint, ie, one by which its effect is partially annulled.
Página 540 - A double and parallel series of facts seems to throw much light on the sterility of species, when first crossed, and of their hybrid offspring. On the one side, there is good reason to believe that slight changes in the conditions of life give vigour and fertility to all organic beings.
Página 506 - a system tends to change so as to minimize an external disturbance." The boughs of a tree bend to the wind in proportion to its strength, when the wind is strong...
Página 376 - An illustrated magazine, established in 1872, devoted to the diffusion of science, publishing articles by leading authorities in all departments of pure and applied science, including the applications of science to education and society. Annual subscription...
Página 249 - It seems not improbable, but that by these helps the subtilty of the composition of Bodies, the structure of their parts, the various texture of their matter, the instruments and manner of their inward motions, and all the other possible appearances of things, may come to be more fully discovered...
Página 280 - The Biology Department maintains research tables at the Marine Biological Laboratory, Woods Hole, Massachusetts, the Mount Desert Biological Laboratory, Maine, and the Bermuda Biological Station. The use of the EM Biological Table in the Laboratory of the United States Bureau of Fisheries at Woods Hole, Massachusetts, together with all the facilities afforded for the collection and study of animal life, is available for a graduate student during the summer. The Zoological Museum includes several...
Página 249 - FIG. 2. comprehend in two general and (unless further explain'd) useless words of Matter and Form. From whence there may arise many admirable advantages, towards the increase of the Operative, and the Mechanick Knowledge, to which this Age seems so much inclined, because we may perhaps be inabled to discern all the secret workings of Nature...
Página 542 - ... that it is not the mere crossing of any two individuals which is beneficial to the offspring. The benefit thus derived depends on the plants which are united differing in some manner, and there can hardly be a doubt that it is in the constitution or nature of the sexual elements. Anyhow, it is certain that the differences are not of an external nature, for two plants which resemble each other as closely as the individuals of the same species ever do, profit in the plainest manner when intercrossed,...