Sinopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922. Excerpt: ... VI PRESENT AND FUTURE EVOLUTION OF MAN A. Physical Evolution Since the beginnings of recorded history there have been very few and wholly minor evolutionary changes in the body of man. Chief among these are the decreasing size of the little toe and perhaps a corresponding increase in the size of the great toe; decreasing size and strength of the teeth, especially of the wisdom teeth; and probably a general lowering of the perfection of sense-organs. These changes are in the main degenerative ones due to the less rigid elimination of physical imperfections under conditions of civilization than in a state of barbarism or savagery. Such changes are insignificant as compared with the enormous changes which led to the evolution of man from prehuman ancestors. Individual variations due to hybridization or to environmental influences are always present but they have little evolutionary value. By hybridization of various races and stocks there has come to be a complicated intermixture of racial charac See Osborn, H. F. "Contemporary Evolution of Man." ters; new combinations of characters are thus produced, but new individual characters have not been evolved by hybridization. By changes in environment modifications have been produced in development but not in heredity, these are fluctuations and not mutations. To a certain extent evolution may be regarded as a response of the organism to environment, whether we have regard to the origin of mutations in the germplasm or to the survival of mutations after they have arisen. But in the case of man the physical environment has probably far less evolutionary value than in lower animals, for by means of intelligence man is able, to a great extent, to control his environment. In cold climates he does not need to grow a th...
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Reseña del editor
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922. Excerpt: ... VI PRESENT AND FUTURE EVOLUTION OF MAN A. Physical Evolution Since the beginnings of recorded history there have been very few and wholly minor evolutionary changes in the body of man. Chief among these are the decreasing size of the little toe and perhaps a corresponding increase in the size of the great toe; decreasing size and strength of the teeth, especially of the wisdom teeth; and probably a general lowering of the perfection of sense-organs. These changes are in the main degenerative ones due to the less rigid elimination of physical imperfections under conditions of civilization than in a state of barbarism or savagery. Such changes are insignificant as compared with the enormous changes which led to the evolution of man from prehuman ancestors. Individual variations due to hybridization or to environmental influences are always present but they have little evolutionary value. By hybridization of various races and stocks there has come to be a complicated intermixture of racial charac See Osborn, H. F. "Contemporary Evolution of Man." ters; new combinations of characters are thus produced, but new individual characters have not been evolved by hybridization. By changes in environment modifications have been produced in development but not in heredity, these are fluctuations and not mutations. To a certain extent evolution may be regarded as a response of the organism to environment, whether we have regard to the origin of mutations in the germplasm or to the survival of mutations after they have arisen. But in the case of man the physical environment has probably far less evolutionary value than in lower animals, for by means of intelligence man is able, to a great extent, to control his environment. In cold climates he does not need to grow a th...
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