Population growth is the result of a balance between biotic potential and environmental resistance





Population growth is the result of a balance between biotic potential and environmental resistance

Population growth may be defined as the increase in the number of individuals in a population. In general a population will tend to increase in number when the available resources are greater than that required by the members of the population present at that particular time. As long as resources are available, every population has the tendency to grow exponentially.
Biotic Potential:
The term biotic potential refers to the highest rate of reproduction possible for a population under ideal conditions, (conditions where birth rate reaches its theoretical maximum). In general, the population increase under these conditions is known as exponential growth. A graph of exponential population growth is said to be J-shaped. Exponential growth is common of populations that have recently been introduced into a new environment, or populations that are recovering from some catastrophe such as a flood. Factors which affect biotic potential include: the age at which reproduction begins (age of first reproduction event), the number of offspring produced at each reproduction event (clutch size), the number of offspring that survive to reproductive age (survival rate), and the number of reproduction events that can occur in the lifetime of the organism. Hence the ability of a population to grow in an unrestricted environment is called its biotic potential. Houseflies and roaches are famous for high biotic potential (one male roach and 19 fertile female roaches can reach the mass of an aircraft carrier in a year). Large slow-gestating animals have much slower biotic potentials
Environmental Resistance:
Environmental resistance is a general term that refers to summative effect of all those factors (known as limiting factors) that reduce the rate of growth of a population. In the mid-1800s, Justus von Liebig noted that plants required essential nutrients for proper growth and development. If even one essential nutrient is in reduced supply, the plant would be affected regardless of the other minerals present. Hence the set of factors which tend to reduce population size or slow reproduction is called environmental resistance
In conclusion the size of a population is set by ability of the individuals to utilize the resources and by the level of those resources (ie, the carrying capacity of the habitat). The more efficiently individuals can utilize resources, the greater their population can be





Bibliography: