The United States contribution to the International Biological Program, which aims to understand more clearly the interrelationships within ecosystems, is centered on multidisciplinary research programs investigating the biological basis of ecological productivity and human welfare. Integrated research programs have been established for the analysis of ecoystems; the study of biological productivity in coastal upwelling ecosystems; the provision of data needed for marine mammal management; the comparison of different ecosystems with similar physical features; the population genetics of South American Indians; the biology of high altitude human populations; and the study of circumpolar peoples. Co-ordinated research projects have been established on the ecology of nitrogen; the biological control of insect pests; aerobiology; phenology; ecosystem conservation; the conservation of plant genetic materials; the biosocial adaptation of migrant and urban human populations; human nutritional adaptation; and human biological rhythms. For each program there are statements of the research objectives, a summary of progress, a list of publications, and the names of participants. (AL)