Experimental Analysis of Population Growth

Abstract

HUMAN populations have always proved favourite material for analysis by statisticians and others interested in mathematical theories of population growth. From the experimental aspect, however, humans are far from being ideal biological material, so that other animals, such as protozoa, mammals and insects, have to be used; although it does not yet appear to be fully realised how suitable the latter are for this type of work. The theory of bio tic potential and environmental resistance¹ has done much to create a new interest in population studies in that it attempts to place the problem upon a quantitative experimental basis. Working with Tribolium confusum, Chapman demonstrated that, irrespective of the initial density, a point of equilibrium is eventually attained after which the population remains relatively constant, provided the floury medium is renewed frequently enough to remove waste products and maintain an abundance of food. He concludes that equilibrium is attained when the bio tic potential is equalled by the environmental resistance, and that the lack of population increase is not due to the absence of eggs or their infertility, but on account of the eating of eggs and pupae by the adult beetles.