The Physical Basis of SocietyD. Appleton and Company, 1916 - 406 من الصفحات |
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الصفحة 204
... germ cells from two sources and that these are segregated in the first " reduction division " we may hazard an explana- tion of the above phenomena . Take the case of the guinea pigs . The black pig came of pure black ancestry and we ...
... germ cells from two sources and that these are segregated in the first " reduction division " we may hazard an explana- tion of the above phenomena . Take the case of the guinea pigs . The black pig came of pure black ancestry and we ...
الصفحة 205
... germ cells or " gametes is revealed thereby . Interesting and significant as these facts are it is im- possible at the present time to tell how far - reaching the Mendelian phenomena are or what practical use may be made of them . On ...
... germ cells or " gametes is revealed thereby . Interesting and significant as these facts are it is im- possible at the present time to tell how far - reaching the Mendelian phenomena are or what practical use may be made of them . On ...
الصفحة 208
... germ cells and that outside influences are of no avail . As early as 1891 Henking discovered that two sorts of sperms occurred in certain insects , the difference depend- ing upon the presence of an odd or " accessory " chromo- some in ...
... germ cells and that outside influences are of no avail . As early as 1891 Henking discovered that two sorts of sperms occurred in certain insects , the difference depend- ing upon the presence of an odd or " accessory " chromo- some in ...
الصفحة 215
... germ cells . In current terms , it was thought that " ac- quired characters " were inherited . To avoid confusion , be it noted that " acquired characters " are changed in the arrangement of the body cells ; that in some fashion these ...
... germ cells . In current terms , it was thought that " ac- quired characters " were inherited . To avoid confusion , be it noted that " acquired characters " are changed in the arrangement of the body cells ; that in some fashion these ...
الصفحة 216
... cells had no influence upon the germ cells . Most people little realize what a mass of corroborative evidence lies easily at hand . Every one knows that the sudden changes produced by ac- cident or disease have no such effect . A man is ...
... cells had no influence upon the germ cells . Most people little realize what a mass of corroborative evidence lies easily at hand . Every one knows that the sudden changes produced by ac- cident or disease have no such effect . A man is ...
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agriculture America aniline appeared Asia average bacteria basis bees believe birds black bass body breeding carbon carbon dioxid carbonic acid cause cent century changes characters chromosomes civilization climate coal color combined considered crops Darwin death destroyed discovered discoveries disease early earth eggs elements environment Europe European evidence evolution exist fact favorable feeble-minded female fish forms germ cells groups heat hence heredity human Ibid idea Inasmuch inches increase individuals influence inheritance insects iron Kallikak Family known Lamarck land large numbers larvæ later less light Linnæus living lower Luther reigned male man's mated natural selection nature Negro normal organisms ovum oxygen parents physical plants and animals possible produced race realize seeds smallpox social soil species square mile substances temperature thought tion tropics women yellow yellow fever
مقاطع مشهورة
الصفحة 155 - Some drill and bore The solid earth, and from the strata there Extract a register, by which we learn, That he who made it, and revealed its date To Moses, was mistaken in its age.
الصفحة 139 - I happened to read for amusement ' Malthus on Population,' and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here then I had at last got a theory by which to work...
الصفحة 58 - Near villages and small towns I have found the nests of humble-bees more numerous than elsewhere, which I attribute to the number of cats that destroy the mice.
الصفحة 139 - In October 1838, that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would...
الصفحة 54 - It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.
الصفحة 186 - The two parents between them contribute on the average onehalf of each inherited faculty, each of them contributing onequarter of it. The four grandparents contribute between them one-quarter, or each of them one-sixteenth ; and so on, the sum of the series i + J + i + TV + , being equal to 1, as it should be.
الصفحة 126 - This fool wishes to reverse the entire science of astronomy; but sacred Scripture tells us that Joshua commanded the sun to stand still, and not the earth.
الصفحة 58 - I am tempted to give one more instance showing how plants and animals, remote in the scale of nature, are bound together by a web of complex relations.
الصفحة 159 - I can conceive in biology would be the discovery of the instability which leads to the continual division of the cell. When I look at a dividing cell I feel as an astronomer might do if he beheld the formation of a double star: that an original act of creation is taking place before me.
الصفحة 58 - I have also found that the visits of bees are necessary for the fertilization of some kinds of clover; for instance, 20 heads of Dutch clover (Trifolium repens) yielded 2,290 seeds, but 20 other heads protected from bees produced not one.