Many factors influence the rate of increase in population. Any population, of any living species is subject to environmental and social factors that influence growth, or decline in population. Researchers have found that population growth tends to follow of a handful of statistical models. “Exponential growth” and “logistic growth” are two of these standard growth patterns.

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## Illustration

Researchers in “demographics,” which is the study of populations, use graphs as part of their standard support methods for their research. Graphs are sometimes referred to as “charts.” These graphs are compiled from gathered statistics and plot levels of population over time. In human populations, the time series is likely to be years. In shorter lived animals and insects, that scale could be months, weeks, or even days. The graph makes it easy to tell, at a glance, what trends are emerging in the growth of the studied population.

## Exponential growth

Exponential Growth means that a population is growing, but not only growing at a standard rate. The rate of increase in each period is higher than the rate of increase in the previous period. With each successive period, the rate of growth increases. With this, the level of population increases by a larger number each period.

## Logistic growth

Logistic growth displays a sudden jump in population. The rate of growth then slows sharply and then levels off. This type of growth, when plotted on a graph, looks like a slim “S.” The sharp decrease in growth rate and then a levelling off of growth to being almost negligible is caused by a factor called “carrying capacity.” This means that the sudden leap in growth was facilitated by some environmental or social factor, which gave the population the ability to grow rapidly. However, the number grows to an extent where resources need to sustain the population can be divided any further.

## Difference

The “carrying capacity” is the crucial difference between exponential growth and logistic growth. In the real world, exponential growth is very rare. A population that seems to be displaying exponential growth is probably only in its upward cycle of a logistic growth pattern. This is because exponential growth will only continue will there are unlimited resources, and resources can never be said to last forever at an ever expanding rate of supply.