 | 1909 - Страниц: 512
...sheep alters, and the cocoon of the silkworm becomes more bulky. The key to all this, says Darwin, is man's power of accumulative selection ; Nature...man adds them up in certain directions useful to him or that satisfy his caprice. In antagonism to the foregoing remarks, one of the most formidable of... | |
 | Western New York Horticultural Society - 1910 - Страниц: 272
...originate? In two sentences Darwin has given the whole philosophy of the origin of varieties. He says, "Nature gives successive variations — man adds them up in certain directions useful to him." Thus, there are two distinct factors in originating varieties. Variation through conditions of growth,... | |
 | Joseph Lane Hancock - 1911 - Страниц: 504
...can and does select variations given him by nature and thus accumulates them in any desired manner. "The key is man's power of accumulative selection,...adds them up in certain directions useful to him. It is the magician's wand by means of which he may summon into life whatever form and mould he pleases."... | |
 | 1911 - Страниц: 786
...practical breeding. The attitude of many appears to be that Darwin was quite mistaken when he wrote, "The key is man's power of accumulative selection:...adds them up in certain directions useful to him." Darwin said, "If selection consisted merely in separating some very distinct variety, and breeding... | |
 | Liberty Hyde Bailey - 1912 - Страниц: 514
...abhors both perpetual self-fertilization and hybridization. LECTURE m. BOW DOMESTIC VARIETIES ORIGINATE. "THE key is man's power of accumulative selection...adds them up in certain directions useful to him." This, in Darwin's phrase, is the essence of the cultivator's skill in ameliorating the vegetable kingdom.... | |
 | Liberty Hyde Bailey - 1913 - Страниц: 506
...both perpetual self-fertilization and hybridization. LECTURE III. HOW DOMESTIC VARIETIES ORIGINATE!. "THE key is man's power of accumulative selection...adds them up in certain directions useful to him." This, in Darwin's phrase, is the essence of the cultivator's skill in ameliorating the vegetable kingdom.... | |
 | Hiram Delos Densmore - 1920 - Страниц: 486
...the desired direction is one of the oldest methods of securing improved races of cultivated plants. " Nature gives successive variations; man adds them up in certain directions useful to himself. . . . The key is man's power of accumulative selection." Darwin thus expressed the essential... | |
 | Charles Coulston Gillispie - 1960 - Страниц: 596
...differentiating by selective breeding the dray horse and the racehorse, the whippet and the dachshund. "The key is man's power of accumulative selection:...adds them up in certain directions useful to him. . . . Breeders habitually speak of an animal's organisation as something plastic, which they can model... | |
 | Peter R. Day - 1969 - Страниц: 196
...purposes, or so beautiful in his eyes, we must, I think, look further than to mere variability. We cannot suppose that all the breeds were suddenly produced...perfect and as useful as we now see them; indeed, in several cases, we know that this has not been their history. The key is man's power of accumulative... | |
 | Charles R. Reid - 1976 - Страниц: 268
...kinds of useful creatures men require. Naturally, we cannot suppose that all the [plant and animal] breeds were suddenly produced as perfect and as useful...may be said to have made for himself useful breeds. The great power of this principle of selection is not hypothetical. 6 Planned human reproduction could... | |
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The key is man's power of accumulative selection: nature gives successive variations; man adds them up in certain directions useful to him. In this sense he may be said to have made for himself useful breeds. 
