When studying a particular population, ecologists consider several characteristics such as geographic range, growth rate, density and distribution, and age structure.

Population growth is based on the addition or removal of individuals in a particular area. The factors that affect population growth include birthrate, death rate, immigration, and emigration.

When there are plenty of resources, a population will grow exponentially; hence an exponential growth occurs. This means that the growth rate increases at a constant rate.

A logistic growth occurs when there is a decrease in population growth once the population reaches its maximum capacity. This can be compared to a pail that is overflowing with water. For a person to be able to carry it without spilling, the excess water must be poured out.

The population size of animals often fluctuates due to the interplay of several factors that are present in an ecosystem. For us to predict the changes in the population growth of rabbits in the meadow, we have to consider the factors such as birth rate, death rate, immigration, and emigration that usually affect the population growth.

In addition, we have to consider the carrying capacity of the meadow, the population density, seasonal changes, and other factors such as availability of food, water, space or shelter, competition, predation, diseases, and natural disasters which can destroy their habitat.

Predicting the population growth of animals are quite difficult to tell since their population size often changes due to the interplay of the different biotic and abiotic factors in an ecosystem. For us to determine the population growth of 5000 horn beetles, we have to consider the birth rate, death rate, immigration and emigration rate, carrying capacity of the forest, the population density, seasonal changes in the region where the forest lies, the lifespan of the beetle, availability of resources, competition for space or shelter, predation, and diseases.