摘要: what were previously independent clusters of more or less co herent theory. Population genetics and population ecology, the most mathematical areas biology, had developed with quite different assumptions techniques, while biogeography is essentially a new field. For genetics, specified by frequencies genotypes without reference to age distribution, physiological state as reflection past history, density. A single species treated at time, evolution usually sumed occur in constant environment. on other hand, recognizes multispecies sys tems, describes populations terms their distributions, phys iological states, densities. The environment allowed vary but are genetically homogeneous, so that ignored. But there increasing evidence demographic time evolu tionary commensurate. Thus biology must deal simultaneously genetic, physiological, heterogeneity within systems changing demographically evolving under fluctuating influences heterogeneous problem how such complex system. naive, brute force approach would be set up model which faithful, one-to-one this complexity. This require using perhaps 100 simultaneous partial differential equa tions lags; measuring hundreds parameters, solving equations get numerical predictions, then these pre dictions against nature. However: (a) too many parameters measure; some still only vaguely defined; lifetime each for measurement.