Laws of Tolerance and Limiting Factor

LAWS OF TOLERANCE AND LIMITING FACTOR

by Antonio C. Antonio

January 30, 2015

Have you ever wondered why we sleep at night and are active during daytime?  Or why the Chinese egret population in Luzon increase in the months of November to February?  Or why certain fruit-bearing trees become productive at certain periods of the year?  The physical characteristics and behavioural patterns of plant and animal species is largely a response to the physical factors of the environment.

“The physical and chemical factors of the environment influence the various metabolic and physiological processes of the organism and regulate their functions.  At the population level, these factors determine the population size of the species present in the community.  Temperature and average annual precipitation are two most critical factors that determine the type of biome present in a geographical area.” (Principles of Ecology: Florece, Espaldon, Cuevas, Sierra & Medina, 1999) 

There are several Laws of Nature that shape the performance of organisms in specific environments.  However, there are two Laws of Nature that govern the specific response of organisms to the physical environment which are the Law of Tolerance and the Law of Limiting Factor.  Curiously though, these two Laws of Nature are inseparable and are never discussed and referred to separately.

“The LAW OF TOLERANCE states that the ability of an organism to survive in a particular habitat or to have the size of a population in a community is determined by its ability to tolerate a range of physical and chemical factors present in the area.  There are three set points of tolerance range.  The highest concentration of the individuals of a population is found within the optimum range where species performs best.  This is the range of the environmental condition most conducive to growth and reproduction of the individuals of the population.  The highest range of condition that the organism tolerates is its maximum range, whereas the lowest range tolerable is known as the minimum range.  No individuals of the species can be found outside of these maximum or minimum ranges.  The upper or lower limits vary with season, geographical region and stages of growth of the species.

The LAW OF LIMITING FACTOR states that a single factor that is either too much or too little determines the growth rate of a species or the presence or absence of its population in a particular place even if all other required factors are in optimum levels.  This factor is called the limiting factor.”  (Principles of Ecology: Florece, Espaldon, Cuevas, Sierra & Medina, 1999) 

The Law of Tolerance refers to the upper and lower bounds to the physical environment that a certain organism can tolerate.  These boundaries affect the ability of a plant or animal organism to function, grow and reproduce.  These changes can either be broad or narrow depending on the seasonal shifts in the tolerance ranges which influence the existence, abundance and distribution of a species in an ecosystem.  These changes are basically physical and chemical in nature.  The Law of Limiting Factors, on the other hand, dictates that these factors are primarily responsible for determining the growth and/or reproduction of an organism in a population.  It may be a physical factor (such as temperature or light) or a biological factor (such as competition among species).  These laws are part of a dynamic gamut of other Laws of Nature that influences the character of life in an ecosystem.  These are the Laws of Tolerance and Limiting Factor.

Just my little thoughts…

(Please visit, like and share Pro EARTH Crusaders on Facebook or follow me at http://antonantonio.blogspot.com/.)