The growth and decline of population in nature and the struggle of species to predominate over one another has been a subject of interest dating back through the ages. Applications of simple mathematical concepts to such phenomena were noted centuries ago. This paper discusses mathematical models in biology, their formulation, analysis and interpretation. Much emphasis is placed on how appropriate assumptions simplify the problem, how important variables are identified and how differential equations are tailored to describing the essential features of a continuous process. The trust of this paper is the application of mathematical models in helping to unravel the underlying mechanisms involved in biological and ecological processes. Afric...