The Genetic and the Operative Evidence Relating to Secondary Sexual CharactersCarnegie Institution of Washington, 1919 - 108 頁 |
其他版本 - 查看全部
常見字詞
Anat appears assumed back-cross bantam barbules barred birds Black-Breasted Game Boring and Pearl breast breeding-season breeds Brown Leghorns capon castrated male castrated Sebright male cock cock-feathered cock-feathered bird color condition courtship coverts crab cross Darwin dominant effect eggs evidence F₁ birds F₁ male F₂ factor for horns feathers fide figure fowl genes genetic germ-cells gonad Goodale hackle hen-feathered males hermaphrodite heterozygous hornless inheritance internal secretion interstitial cells Leghorn luteal cells male and female male plumage male Sebright mammals mating Merino molt natural selection normal male nuptial plumage operation organs ornamentation ovary oviduct papillæ pheasants plumes poultry present produced races recessive removed Sacculina secondary sexual characters sex chromosomes sex-limited sex-linked sexual selection shown in plate species stippled T. H. MORGAN tail feathers tail-coverts testes testicular testis theory of sexual tion tissue tubules wing-bow wings yellow Zool
熱門章節
第 55 頁 - On May 24th we found a mature female, and placed her in one of the larger boxes, and the next day we put a male in with her. He saw her as she stood perfectly still, twelve inches away; the glance seemed to excite him, and he at once moved toward her; when some four inches from her he stood still, and then began the most remarkable performances that an amorous male could offer to an admiring female. She eyed him eagerly, changing her position from time to time so that he might be always in view....
第 100 頁 - PEARL, 1917. Sex studies, IX. Interstitial cells in the reproductive organs of the chicken. Anat.
第 14 頁 - Hewitt64 possessed an excellent Sebright gold-laced bantam hen, which, as she became old, grew diseased in her ovaria, and assumed male characters. In this breed the males resemble the females in all respects except in their combs, wattles, spurs, and instincts ; hence it might have been expected that the diseased hen would have assumed only those masculine characters which are proper to the breed, but she acquired, in addition, well-arched tail sickle-feathers quite a foot in length, saddlefeathers...
第 76 頁 - The sixth age shifts Into the lean and slipper'd pantaloon, With spectacles on nose and pouch on side, His youthful hose, well saved, a world too wide For his shrunk shank ; and his big manly voice, Turning again toward childish treble, pipes And whistles in his sound. Last scene of all, That ends this strange eventful history, Is second childishness and mere oblivion, Sans teeth, sans eyes, sans taste, sans everything.
第 55 頁 - He moved in a semicircle for about two inches, and then instantly reversed the position of the legs, and circled in the opposite direction, gradually approaching nearer and nearer to the female. Now she dashes...
第 55 頁 - ... her ; when some four inches from her he stood still, and then began the most remarkable performances that an amorous male could offer to an admiring female. She eyed him eagerly, changing her position from time to time so that he might be always in view. He, raising his whole body on one side by straightening out the legs, and lowering it on the other by folding the first two pairs of legs up and under...
第 60 頁 - ... muscular movements. The male does not immediately embrace the female, for in most spiders he is the weaker individual, but delays in order to first determine whether the female is eager or hostile. Rhythmically repeated motions of the male during this period of delay constitute courtship, and these motions are for the most part exaggerations of ordinary motions of fear and timidity. By such motions he advertises himself to the female as a male, but there is no proof that he consciously seeks...
第 48 頁 - ... rise up and fly to them, leaving his own mate to guard their chosen ground ; and instead of resenting this visit as an unwarranted intrusion on their domain, as they would certainly resent the approach of almost any other bird, they welcome it with notes and signs of pleasure. Advancing to the visitor, they place themselves behind it; then all three, keeping step, begin a rapid march, uttering resonant drumming notes in time with their movements; the notes of the pair behind being emit ted in...
第 85 頁 - ... growth of a deer's antlers. Early in the following spring individual tanagers and bobolinks were gradually brought under normal conditions and activities, with quick result: just as the wild birds in their winter haunts in South America were at that time shedding their winter garb and assuming the more brilliant hues of summer, so the birds under my observation also moulted into the colors appropriate to the season. The old scarlet and black feathers fell from the tanagers and were replaced by...
第 46 頁 - ... and other erectile feathers may have been safeguards for the bird by making it more formidable in appearance and thus frightening away enemies ; that long tail- or wingfeathers might serve to distract the aim of a bird of prey ; and that the ornamental appendages of birds and other animals are due to a surplus of vital energy, leading to abnormal growths in those parts of the integument where muscular and nervous action are greatest.1 If the primary object of secondary sexual characters is to...