Readings in Evolution, Genetics, and Eugenics (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 edition. Excerpt: ...as is (1) the intra-specific struggle among the thousands of honey-bee individuals living together altruistically, in one hive, or (2) the inter-specific struggle, when two species live together symbiotica.lly as the hermit crab Eupagurus and the sea-anemone Podocoryne, or (3) the struggle against untoward natural conditions as in special times or places of highly favourable climate, etc. Or for any individual or group of individuals all forms of the struggle may be coincidently active and severe. The resultant of these existing conditions is, according to Darwin and his followers, an inevitable natural selection of individuals and of species. Thousands must die where one or ten may live to maturity (i.e., to the time of producing young). Which ten of the thousand shall live depends on the slight but sutficicnt advantage possessed by ten individuals in the complex struggle for existence due to the fortuitous possession of fortunate congenital differences (variations). The nine hundred and ninety with unfortunate congenital variations are extinguished in the stmggle and with them the opportunity for the perpetuation (by transmission to the offspring) of their particular variations. There are thus left ten to reproduce their advantageous variations. The offspring of the ten of course will vary in their turn, but will vary around the new and already proved advantageous parental condition: among the thousand, say, offspring of the original saved ten the same limitations of space and food will again work to the killing off before maturity of nine hundred and ninety, leaving the ten best equipped to reproduce. This repeated and intensive selection leads to a slow but steady and certain modification through the successive generations of the form...