The American Naturalist, Volume 47Essex Institute, 1913 |
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Termos e frases comuns
ABDP abnormal adaptation alcoholic allelomorphs ancestors animals apogamy appear bicolor biennis bipunctata birds body breeding brown cent Chaetognatha characters chromosomes coefficients color cross culture distribution dwarfs echinoderms Eldonia embryos enflata Enothera entelechy environment evidence evolution experimental experiments F₂ fact factors fasciated fathoms female fertilization fishes flowers formulæ gametes genera genetic genus germ cells germinal grandiflora heterozygous hexaptera holothurian homozygous host hybrids inbreeding individuals inheritance Lamarckiana larvæ left-handed letters living male Mallophagan species mammæ matings mature Mendelian ment Minus differences mutation natural selection normal obtained occur offspring organism pair paper papillæ Paramecium parasite parent parthenogenesis pedigree plankton plants pollen polyembryony possible present probably produced ratio represented rosettes scutes seeds serratodentata somatic specimens spermatozoa spotted stages statoblasts structure tabacum TABLE teosinte theory tion tricolor black variability variation vertebræ vitalistic young
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Página 130 - germ-plasm,' and have assumed that it possesses a highly complex structure, conferring upon it the power of developing into a complex organism. I have attempted to explain heredity by supposing that in each ontogeny, a part of the specific germ-plasm contained in the parent egg-cell is not used up in the construction of the body of the offspring, but is reserved unchanged for the formation of the germ-cells of the following generation.
Página 107 - Darwinian fitness is compounded of a mutual relationship between the organism and the environment. Of this, fitness of environment is quite as essential a component as the fitness which arises in the process of organic evolution; and in fundamental characteristics the actual environment is the fittest possible abode of life.
Página 579 - Papers from the Biological Laboratory of the Maine Agricultural Experiment Station. No.
Página 587 - We may first consider some simple hypothetical pedigrees, before attacking the more complicated ones actually realized in stock-breeding. Illustration I. Continued Brother X Sister Breeding Let us begin with the most extreme type of inbreeding possible, namely the mating of brother with sister for a series of generations. Pedigree Table III gives the pedigree of an individual so bred. PEDIGREE TABLE III. (Hypothetical) To Illustrate the Breeding of Brother X Sister, out of Brother X Sister, Continued...
Página 126 - Therefore each individual may properly be conceived as consisting of two parts, one of •which is latent and only known to us by its effects on his posterity, while the other is patent, and constitutes the person manifest to our senses.
Página 130 - highly complex structure conferring upon it the power of developing into a complex organism," and heredity was further explained "by supposing that In each ontogeny a part of the specific germ plasma contained In the parent egg-cell is not used up in the construction of the body of the offspring, but is preserved unchanged for the formation of the germ cells of the following generation.
Página 656 - ... tank, having a similar screen arrangement to that of the general treatment tank. The pregnant animal may be driven daily into the tank and thus treated with alcohol fumes throughout her pregnancy without being handled in any way that might disturb the developing fetus. DIRECT EFFECTS OF TREATMENT. Many of the animals have now been treated almost to the point of intoxication for six days per week for nearly three years. They are affected by the alcohol fumes in different ways; certain ones become...
Página 126 - The adjacent and, in a broad sense, separate lines of growth in which the patent and latent elements are situated, diverge from a common group and converge to a common contribution, because they were both evolved out of elements contained in a structureless ovum, and they, jointly, contribute the elements which form the structureless ova of their offspring.
Página 542 - Chronicle seems a little stronger than in Mr. Matthew's book, for the passages are therein scattered in three places; but it would be mere hair-splitting to notice that. If you object to my letter, please return it ; but I do not expect, that you will, but I thought that you would not object to run your eye over it. '"The Life and Letters of Charles Darwin,
Página 125 - Not all the progeny of the primary impregnated germ-cell are required for the formation of the body in all animals: certain of the derivative germ-cells may remain unchanged and become included in that body which has been composed of their metamorphosed and diversely combined or confluent brethren : so included, any derivative germ-cell or the nucleus of such may commence and repeat the same processes...