Extended logistic model for growth of single-species populations

A procedure for constructing models of population growth is presented. It consists of three assumptions: resource availability changes with population size as a variable, resource supply to a population and population demand for resources function as a field and a boundary, respectively, and the variables move on the field to the boundary. These are organized into an equation similar in form to Verhulst’s model. The equation can determine boundaries necessary for classical models at a certain field. It is shown that most of the models include complex boundaries. The equation also provides a new growth model when the field and boundary are approximated using a linear function and a quadratic function, respectively, of resource availability and population size. One of the parameters in this model is defined as the type and intensity of intraspecific interaction.