| the genetical response to natural selection by varied environments. ii. observations on replicate populations in spatially varied laboratory environments. | from each of two populations of drosophila melanogaster, collected two months previously, from chateau tahbilk, s. australia and groningen, the netherlands, duplicate populations were initiated in each of four environments which differed in their degree of environmental heterogeneity. differing combinations of three food media based on oatmeal/treacle, potato or fig were used to simulate levels of environmental heterogeneity within the populations. the polymorphic loci, adh, est-6, g-6pdh, alpha ... | 1983 | 6421776 |