Ecology is far more than a delineated portion of biology. Just as genetics and evolution are ways of approaching the measurement and interpretation of all biological phenomena, so is ecology. Because man is a biological entity, everything he does has biological, hence ecological, implication. A variety of human activities are within the professional scope of ecology, including man's relations with his environment and man's population dynamics. Since the primary variable controlling these activities is human behavior, ecologists who are working to protect man's environment must deal in part with human behavior. Furthermore, since the study of population dynamics is a chosen specialty of ecologists, and since a major factor in man's environmental crisis is his growing density, ecologists concerned with the future of humanity cannot avoid some involvement with efforts to stabilize human numbers.