Can the population of any species grow exponentially?

AUTHOR - Kamayani Richhariya

The size of a population for any species is a dynamic parameter that depends upon various factors like availability of food, adverse weather, predation pressure, etc. Whatever might be the reason for the change in population density, can the population of any species grow exponentially? To answer this question, let us first look at the four basic processes contributing to change in population density.

1) Natality refers to the number of births during a given period.

2) Mortality refers to the number of deaths in the population during a given period

3) Immigration is the number of individuals (of the same species) that have come into the habitat from somewhere else.

4) Emigration is the number of individuals of the population who abandoned the habitat to live somewhere else.

Growth models:- Environmental scientists use two growth models to predict the growth pattern of any population, which are discussed below:-

1) Exponential growth:- According to observations of Darwin while developing his theory of natural selection, when resources in the habitat are unlimited, each species can realise fully its innate potential to grow in number. In such conditions, the population grows in an exponential or geometric fashion. Any species, having unlimited resources, which is growing exponentially can reach enormous population densities in a very short period of time.

2) Logistic growth:- Since the resources present in the world are limited, the logistic growth model is considered a more realistic model. In reality, there is a competition between individuals for the limited resources and subsequently, the “fittest” individual survives and reproduces. Nature has a limited amount of resources that can support a maximum possible number beyond which no growth is further possible. This maximum number is called nature’s carrying capacity for the specified species in the given habitat and is denoted by “K”. When a plot between population density and time is drawn, the asymptote of the graph denotes nature’s carrying capacity.