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. 1920 edition. Excerpt: ...arising in the same way, there is no special difficulty in understanding their persistence on this theory. For variations that arise from within have often great staying power in inheritance. The Germinal Origin of Improvements in Instinctive Behaviour. We must linger over the difficulty, which many biologists ...
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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. 1920 edition. Excerpt: ...arising in the same way, there is no special difficulty in understanding their persistence on this theory. For variations that arise from within have often great staying power in inheritance. The Germinal Origin of Improvements in Instinctive Behaviour. We must linger over the difficulty, which many biologists feel acutely, of trying to account for improvements in instinctive behaviour by variations in the germ-cell. When an organ, such as the proboscis of an elephant, has shown in successive ages a gradual increase and differentiation, as the skulls of fossil Proboscidea seem to indicate, the non-Lamarckian evolutionist supposes that this is due to the selection of variants in the direction of elongation, these variants being the expressions of appropriate changes in germinal organisation. The change in germinal organisation, say a strengthening of certain primary constituents, operates during the active process of proboscis-development, or of proboscis-growth, for it need not begin to exert its influence until long after the foundations have been laid. Thus a long-billed bird need not show much or anything in the way of a long bill until after it is hatched. The general idea is that an improvement of structure comes about as the expression of a germinal variation which asserts itself during the activity of development or growth. It is not necessary to think of it as asserting itself only once, for the highly differentiated structure, such as a snail's horn or a newt's lens, may be regrown if it be lost. The germinal variation includes a residual capacity (localised at the base of the horn or in the tissue near the lens) for reproducing or regenerating what has been lost. The general idea, we repeat, is that a cumulative germinal variation, ..
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
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Good. 2-volume set. Ex-library copies with usual markings. Covers shows minor wear and tear. Pages are lightly tanned and clean. Very Clean Copy-Over 500, 000 Internet Orders Filled.
