Question

How do you determine carrying capacity?

Answer 1

The carrying capacity is defined for a population of living organisms present in an ecosystem and its value changes for different organisms as well as different ecosystems. It is indirectly the value of the maximum number of organisms that can exist for that population.

Complete Answer:
Nature, in general, has a maximum capacity up to which it can carry organisms of a specific population after which any high number of organisms will not be able to exist. This maximum capacity is known as nature’s carrying capacity for that species to allow them to thrive in that particular habitat. Carrying capacity is a measure of the resources available in a habitat for organisms to utilize. Factors like carrying capacity play a major role during logistic growth which is the type of growth where unlimited resources are not provided to a species and thus they cannot reproduce to their full potential. So, in log growth, there is a lag phase after which there is an acceleration, deacceleration phases finally reaching an asymptote phase when the population has reached the carrying capacity value. Such a type of growth when plotted on a graph shows a sigmoid type of curve. And the carrying capacity is given by the equation:
$\dfrac { dN }{ dt } =\quad rN\left( \dfrac { K-N }{ K } \right)$

Additional information:
-Another type of growth is exponential growth when resources such as food and space are provided in unlimited amounts thus allowing a species to grow in exponential fashion.
-The curve that is obtained during exponential growth is J-shaped.
-While determining exponential growth, the ‘intrinsic rate of natural increase’ represented as ‘r’ plays an important role as it tells us the impact of biotic abiotic factors on the growth of the population.
-The value of r for humans in 1981 was 0.0205 whereas for Norway rats it is 0.015 and for flour beetles, it is 0.12.

Note:
-Logistic growth is also known as Verhulst-Pearl Logistic Growth and it is the type of growth seen in real life.
-The limited resources in logistic growth force organisms to compete with each other and thus survival of the fittest takes place.
-Such an organism will leave more offspring and with time, natural selection will take place to select a better-suited species for the habitat.