The powerful retractile talons of the falcon- and the cat-tribes have not been produced or increased by the volition of those animals; but among the different varieties which occurred in the earlier and less highly organized forms of these groups, those always survived longest which had the greatest facilities for seizing their prey. Neither did the giraffe acquire its long neck by desiring to reach the foliage of the more lofty shrubs, and constantly stretching its neck for the purpose, but because any varieties which occurred among its antitypes with a longer neck than usual at once secured a fresh range of pasture over the same ground as their shorter-necked companions, and on the first scarcity of food were thereby enabled to outlive them. [...] We believe we have now shown that there is a tendency in nature to the continued progression of certain classes of varieties further and further from the original type - a progression to which there appears no reason to assign any definite limits - and that the same principle which produces this result in a state of nature will also explain why domestic varieties have a tendency to revert to the original type. This progression, by minute steps, in various directions, but always checked and balanced by the necessary conditions, subject to which alone existence can be preserved, may, it is believed, be followed out so as to agree with all the phenomena presented by organized beings, their extinction and succession in past ages, and all the extraordinary modifications of form, instinct, and habits which they exhibit.
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"On the Tendency of Varieties to Depart Indefinitely From the Original Type" (1858)Alfred Russel Wallace
» Alfred Russel Wallace - all quotes »
Well, which is the most rational theory about these ten millions of species? Is it most likely that there have been ten millions of special creations? or is it most likely that, by continual modifications due to change of circumstances, ten millions of varieties have been produced, as varieties are being produced still?
Herbert Spencer
Henry Fairfield Osborn, the dominant paleontologist of his era, and long time director of the American Museum of Natural History, gave the "standard version in his popular book of 1918, The Origin and Evolution of Life... "Lamarck attributed the lengthening of the [giraffe's] neck to the inheritance of bodily modifications caused by the neck-stretching habit. Darwin attributed the lengthening of the neck to the constant selection of individuals and races which were born with the longest necks. Darwin was probably right." ...The version has held ever since.
Stephen Jay Gould
If the neck of the giraffe elongates an inch at a time, then the full panoply of supporting structures need not arise at every step. The coordinated adaptation can be built piecemeal. Some animals may slightly elongate the neck, others the legs; still others may develop stronger neck muscles. By sexual reproduction, the favorable features of different organisms may be combined in offspring.
Stephen Jay Gould
"'The battle to feed all of humanity is over," biologist Paul Ehrlich famously wrote in his 1968 bestseller The Population Bomb ... But Borlaug and his team were already engaged in the kind of crash program that Ehrlich declared wouldn't work. Their dwarf wheat varieties resisted a wide spectrum of plant pests and diseases and produced two to three times more grain than the traditional varieties ... Borlaug, who unfortunately is far less well-known than doomsayer Ehrlich, is responsible for much of the progress humanity has made against hunger."
Norman Borlaug
The differences between the two sexes is one of the important conditions upon which we have built the many varieties of human culture that give human beings dignity and stature.
Margaret Mead
Wallace, Alfred Russel
Wallace, David Foster
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