This and the following sections will discuss the historical growth rate of the human population, and introduce you to some basic population parameters. We'll start with:
G = B - D
where:
G = population growth rate (change in numbers over time)
B = birth rate (absolute number of births per time interval)
D = death rate (absolute number of deaths per time interval)
(This equation ignores the influence of migration on population growth. We will do the same for the most part, because we are primarily concerned with global population growth [hence migration isn't relevant -- at least so far!].)
Terms such as birth and death rates are "demographic parameters;" terms that describe population status and growth. ("Demography" is the statistical study of population dynamics [changes over time] and descriptors of populations.)
The (crude) figure below illustrates some simple patterns that could be observed in population growth.
For example, when there is no change in number with time (zero slope) then B = D and G then = 0; that is, the population is not growing.
The negative slope implies a shrinking population (B < D) and therefore a negative G.
Positive slopes imply growing populations (B > D), with the steepness of the slope indicating the rapidity of growth.
(Click ">>" box at the bottom to move to the next section (on historical factors influencing growth rates) now; "<<" box to move to preceding section, "Contents" box to return to master directory for the BI301 web site. "Navigate " gives general reminders on how to do that.)
