The impact of high altitudes on human populations.

Abstract

EVERY ecological situation involves complex interactions between the varions components of an environment. Physical elements interact with each other to determine the total impact they make on living organisms, and these biotic elements not only determine each other, but react back to affect physical conditions. Here we shall be primarily concerned with the human situation, with the way man is affected by one type of environment complex and, to a lesser extent, with the way he himself affects this complex. Making one organism the focus of attention can distort the whole ecological picture, but our concern is with the challenge imposed on man by the many high altitude environments of the world. There are many components in the successful occupation of an environment, individual adaptability at both the physiological and developmental levels, specific genetic adaptations produced by natural selection in the environment, and particularly important in man, cultural and technological factors which allow him to avoid, or at least to modify, the stressful components in the environment. These components themselves function in an interacting way, and determine the average levels of fitness - both Darwinian and physical - in populations. Environments, of course, also act in a more general way on Ьитал populations; they determine size, density and distributions, they limit the types of economies which can be practised, and to varying degrees affect general social structure. And these factors themselves may then have profound influences on human biology and for that matter on the total ecology of an area.