Chapter 8 Understanding Population Change

1. Chapter 8 – Understanding Population Change Population ecology – refers to the study of a defined population of organisms, in a given area, and how and why population changes occur over a period of time. Among issues of interest are how individuals compete for food and other resources, and how environ-mental pressures, e.g., predation, disease, may affect the population. Also of interest is the reproductive health of the population and “Does this population seem to be inter-acting with its ecosystem in a normal manner?”. We could look at age distribution w/in the population, too.

2. In order to define characteristics of a population, physical boundaries of the population need to be defined. Population density – number of individuals per unit area (land) or unit volume (water). Variable between different ecosystems & seasonally depending on availability of food & other needs. On a large scale, population changes occur by births (birth rate/1000/year) & deaths (death rate/1000/year). The growth rate is the birth rate minus death rate.