It is also called reproductive potential. Populations cannot grow exponentially indefinitely because there is always limit put by nature to the population growth. Exponential growth results in exploding populations, which ultimately reaches a size limit imposed by the shortage of one or more factors such as water, space, and nutrients or by adverse conditions such as disease, drought and temperature extremes, etc. The interrelation between the biotic potential and environmental resistance keeps a population in balance.
Carrying Capacity:. If there are 10 Burgers and 10 people sit down at a lunch table, and if it is decided to distribute the food equally, each one will get 1 burger. If the number of people increases, everybody will get less than one.
This is what happens in nature. If organisms that cannot get food will die or find a new place to live. The carrying capacity of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water, and other necessities available in the environment.
The carrying capacity of any area is not static. It may be lowered by resource destruction and degradation during an overshoot period or extended through technological and social changes. For populations which grow exponentially, growth starts out slowly, enters a rapid growth phase and then levels off when the carrying capacity for that species has been reached. The size of the population then fluctuates slightly above or below the carrying capacity.
In contrast, when the population is below the carrying capacity, the environment can favourably sustain the population, fulfilling all the requirements giving food, habitat, water, and other necessities available in the environment. There are two types of factors affecting the carrying capacity of a species.
They are internal factors and external factors. Interspecific competition for space, food, or light, life-history traits, and cannibalism are some internal factors while environmental conditions are the main external factor that affects the carrying capacity.
The biotic potential is the maximum reproductive capacity of an organism under optimum environmental conditions while carrying capacity is the maximum population of a species the environment can support sustainably. So, this is the key difference between biotic potential and carrying capacity.
Moreover, another difference between biotic potential and carrying capacity is the factors affecting each. Predation, competition, parasitism, diseases, climatic conditions lack of space, light , fire and temperature, etc. Below is a summary of the difference between biotic potential and carrying capacity in tabular form. The biotic potential is the rate at which a species reproduces with unlimited resources and environmental conditions.
For populations which grow exponentially, growth starts out slowly, enters a rapid growth phase and then levels off when the carrying capacity for that species has been reached. The size of the population then fluctuates slightly above or below the carrying capacity. Reproductive lag time may cause the population to overshoot the carrying capacity temporarily.
Reproductive lag time is the time required for the birth rate to decline and the death rate to increase in response to resource limits. In this scenario, the population will suffer a crash or dieback to a lower level near the carrying capacity unless a large number of individuals can emigrate to an area with more favorable conditions. An area's carrying capacity is not static. The carrying capacity may be lowered by resource destruction and degradation during an overshoot period or extended through technological and social changes.
An example of dieback occurred in Ireland after a fungus infection destroyed the potato crop in During this potato famine approximately 1 million people died and 3 million people emigrated to other countries. The picture below shows an example of a carrying capacity graph Figure 1. Here, the carrying capacity symbol: K for a biological species is marked by the red dotted horizontal line to describe the number of organisms that the environment can support sustainably for a given time.
Notice that it coincides with the stable equilibrium , which refers to the population size that has reached a steady-state as it aligns with the carrying capacity. The growth is depicted as S-shaped a characteristic of a logistic growth.
The S-shape logistic growth forms when the growth rate is slow at first lag phase and next speeds up exponential phase. Then, the rate slows down again as the population size reaches carrying capacity. In the real world, though, population size tends to rise and dip in oscillations from the carrying capacity rather than a flat line as depicted in the graph.
To calculate for the carrying capacity K , the equation for the change of population size can be used for deriving a formula for K Ref.
A sample worksheet of carrying capacity and population biology can be found here. A population may grow at a faster rate and follow a J-shaped curve. When the birth rate surpasses the death rate of the species, this results in exponential growth. However, this trend soon changes as resources become limited. The growth rate slows down. Soon, it reaches a stable equilibrium where biomass in the given area seems unchanged over a certain period of time. At this point, the death rate appears to be compensated by the birth rate within a population.
This means the per capita birth rate equals the per capita death rate. By contrast, when deaths appear to outgrow births, this indicates that the carrying capacity has been exceeded.
This is a case of overshoot. The population may go below the carrying capacity. This can occur, for instance, during disease and parasitic outbreaks. Several factors affect the carrying capacity of an ecosystem.
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