Biology 2483A Lecture 8: Population Dynamics
Document Summary
Population dynamics: the ways in which populations change in abundance over time. Population size changes as a result of four processes: birth, death, immigration, and emigration. Patterns of population growth: populations exhibit a wide range of growth patterns, including exponential growth, logistic growth, fluctuations and regular cycles, these four patterns are not mutually exclusive. A single population can experience each of them at different times. Exponential growth: population increases by a constant proportion at each point in time, when conditions are favorable, a population can increase exponentially for a limited time. When a species reaches a new area, exponential growth can occur if conditions are favorable: the population may grow exponentially until density-dependent factors regulate its numbers. Species such as the cattle egret colonize new regions by long-distance or jump dispersal events. Local populations then expand by short-distance dispersal events.