 ... to natural selection, by affording a better chance of the occurrence of profitable variations. Unless such occur, natural selection can do nothing. Under the term of " variations," it must never be forgotten that mere individual differences are included.  The American Naturalist - Página 1481909Vista completa - Acerca de este libro
 | Charles Darwin - 1873 - 492 páginas
...would tend to be preserved ; and natural selection would have free scope for the work of improvement. We have good reason to believe, as shown in the first chapter, that changes in the.conditions of life give a tendency to increased variability; and in the foregoing cases the conditions... | |
 | Charles Darwin - 1875 - 504 páginas
...would tend to be preserved.; and natural selection would have free scope for the work of improvement. We have good reason to believe, as shown in the first...conditions have changed, and this would manifestly be favourable to natural selection, by affording a better chance of the occurrence of profitable variations.... | |
 | Charles Darwin - 1896 - 406 páginas
...would tend to be preserved ; and natural selection would have free scope for the work of improvement. We have good reason to believe, as shown in the first...conditions have changed, and this would manifestly be favourable to natural selection, by affording a better chance of the occurrence of profitable variations.... | |
 | Charles Darwin - 1896 - 408 páginas
...would tend to be preserved ; and natural selection would have free scope for the work of improvement. We have good reason to believe, as shown in the first...conditions have changed, and this would manifestly be favourable to natural selection, by affording a better chance of the occurrence of profitable variations.... | |
 | Charles Dudley Warner - 1897 - 494 páginas
...would tend to be preserved; and Natural Selection would have free scope for the work of improvement. We have good reason to believe, as shown in the first...chance of the occurrence of profitable variations. Unless such occur, Natural Selection can do nothing. Under the term of " variations, " it must never... | |
 | Dennis Hird - 1903 - 260 páginas
...Natural Selection would have free scope for the work of improvement. " We have good reason to believe that changes in the conditions of life give a tendency to increased variability ; and, in the foregoing case, the conditions have changed, and this would manifestly be favourable to Natural Selection by... | |
 | Walter Warren Seton - 1903 - 168 páginas
...... in the great and complex battle of life should occur . . . ? " 3 On the next page he observes, " Changes in the conditions of life give a tendency to increased variability. . . . Unless such profitable variations occur, natural selection can do nothing.1" The wild carrot,... | |
 | Oliver Joseph Thatcher - 1907 - 494 páginas
...would tend to be preserved; and natural selection would have free scope for the work of improvement. We have good reason to believe, as shown in the first...conditions have changed, and this would manifestly be favourable to natural selection, by affording a better chance of the occurrence of profitable variations.... | |
 | 1909 - 784 páginas
...during many generations to absolutely uniform conditions of life, there would be no variability.11 We have good reason to believe, as shown in the first...affording a better chance of the occurrence of profitable variations.13 Use and Disuse. It is notorious, and we shall immediately adduce proofs, that increased... | |
 | Charles Darwin - 1909 - 584 páginas
...would tend to be preserved ; and natural selection would have free scope for the work of improvement. We have good reason to believe, as shown in the first...changes in the conditions of life give a tendency to increasecT variability';" and in the Foregoing cases the conditions have changed, and this would manifestly... | |
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