Word: darwinian
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
Wilson asserts that "the summed Darwinian fitness of the tribe" is "the ultimate if unrecognized beneficiary of warfare" and speaks of "the true biological joy of warfare...
...variants that deviate too far in any direction from the well adapted norm. But when the environment is changed the same basic process of natural selection has a diversifying effect: the new circumstances select for the preferential survival and reproduction of variants with increased fitness for those circumstances. This Darwinian process explains a phenomenon that confused early workers: when pathogenic bacterial strains are isolated from infected hosts and then repeatedly transferred in artificial culture media they often rapidly lose virulence. We now know the mechanism by which this improved adaptation to the new environment occurs, at the expense of decreased...
...continuous spectrum of genetic patterns, and the borders between what we call bacterial species are arbitrary and often controversial. E. coli, for example, is the name given to a range of strains with certain common features but also with a variety of differences, and these differences determine their relative Darwinian fitness for various environments. This elementary concept was entirely missing from Cavaliere's discussion of the hazards of inserting genes in E. coli in the New York Times Sunday Magazine last August, and I would criticize the Times for publishing such a polemical and unqualified account...
...bacterial strains called E. coli thrive only in the vertebrate gut, and because these cells die out rather quickly in water the E. coli count of a pond or a well is a reliable index of its continuing fecal contamination. In the gut there is intense Darwinian competition between strains, depending on such variables as growth rate, growth requirements, ability to scavenge traces of food, adherence to the gut linings and resistance to antimicrobial factors in the host. Hence most novel strains are quickly extinguished. The mechanism of this extinction is the kind of selection by competition envisaged by Darwin...
...would have them admit students at a later point," Martin says. Under this proposal, sophomore tutorials in elite majors would be open to all, and selection by the limited concentrations would occur before junior year. The second alternative would open enrollment to all, using severe requirements to encourage a Darwinian type of natural selection. As Martin admits, there are valid arguments in favor of both proposals--and in favor of no changes--and the Faculty, which in this case must make the final decision, will undoubtedly gear itself up for a heated dispute...