Biology 2483A Lecture 10: Ecology Lecture No. 10.docx

• School: Western University
• Department: Biology
• Course: Biology 2483A
• Professor: Hugh Henry

Document Summary

Population dynamics describes the ways in which populations change in abundance over time. Population size changes as a result of four processes: birth, death, immigration, and emigration. This can be simplified in the following equation: Where n t is the population size at time t. N t + 1 = n t + b d + i e. Populations exhibit a wide range of growth patterns, including exponential growth, logistic growth, fluctuations, and regular cycles. A single population can experience each of them at different times. Exponential growth is where the 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.