Chapter 4: Part One The Human Population and the Environment

Basic Concepts of Population Dynamics Population: –A group of individuals of the same species living in the same area in the same time period Species: –All individuals that are capable of interbreeding. –Made up of populations Population dynamics –The study of population changes. Demography -

Forecasting Population Change Formula to represent population change: P 2 = P 1 + (B – D) + (I – E) P = B = D = I = E =

Age Structure Population age structure: –The proportion of the population in each age class –Affects current and future birth rates, death rates and growth rates –Has an impact on the environment –Has complications for current and future social and economic status.

© 2008 John Wiley and Sons Publishers

A Brief History of Human Population Growth 1. Hunters and gatherers The world’s population was probably less than a few million 2.Early, pre-industrial agriculture Allowed a much greater density of people The first major increase in human population 3.Machine age Industrial revolution led to rapid increase in human population 4.The Modern era Rate of population has slowed in wealthy nations but continues to increase rapidly in poorer, less developed nations.

© 2008 John Wiley and Sons Publishers

Projecting Future Population Growth Exponential growth and doubling time The logistic growth curve – “S” shaped curve that is generated by the logistic growth equation. A small population grows rapidly But the growth rate slows down The population eventually reaches a constant size. Logistic carrying capacity –The population size at which births equal deaths and there is no net change in population

© 2008 John Wiley and Sons Publishers