Principles of Environmental Factors

Principles of Environmental Factors The principles of environmental factors are the basic principles that explain how environmental factors affect the life of organisms. Chapter 9 of the book "Ecology: Populations, Communities, Ecosystems" discusses two main principles, namely Liebig's Minimum Law and Shelford's Law of Tolerance. Let's discuss it in more detail, complemented by additional information from broader ecological knowledge: 1. Liebig's Minimum Law This law, put forward by Justus von Liebig, a German agricultural chemist in the 19th century, states that the growth of an organism will be limited by the least available element or compounds in its environment, even if the other elements necessary for growth are available in sufficient quantities. These limiting elements or compounds are referred to as limiting factors. For example, plants need various nutrients such as nitrogen, phosphorus, and potassium to grow. If the soil is deficient in phosphorus, even though nitrogen and potassium are available in sufficient quantities, the growth of the plant will be stunted by the lack of phosphorus. In this case, phosphorus is a limiting factor. Application of Liebig's Law Liebig's Law has important implications in agriculture and natural resource management. By identifying limiting factors, we can increase plant productivity by adding fewer nutrients. However, it is important to remember that excessive addition of nutrients can also lead to environmental problems, such as water pollution. 2. Shelford's Law of Tolerance This law, put forward by Victor Ernest Shelford, an American ecologist in the early 20th century, expands on Liebig's Law by stating that organisms have not only a minimum limit for environmental factors, but also a maximum limit. Organisms can only survive and multiply within a certain tolerance range for each environmental factor. For example, trout need cold water temperatures to survive. If the water temperature is too high or too low, the trout will die. The range of water temperatures that a trout can tolerate is its tolerance range. Additional Principles of Shelford's Law of Tolerance • Organisms can have a wide tolerance range for one factor and a narrow tolerance for another. For example, some plants can tolerate varying levels of soil moisture, but they can only grow within a certain temperature range. • Organisms with a wide tolerance range for all factors tend to have a wider geographical distribution. • If conditions are not optimal for one factor, the tolerance limit for other factors may narrow. For example, if plants are deprived of water, they may become more sensitive to high temperatures. • The reproductive period is a critical period and has a narrower tolerance for all factors. This is because young organisms are more susceptible to environmental changes than adult organisms. Application of the Law of Tolerance Shelford's Law of Tolerance has important implications for understanding the distribution of organisms in nature. By knowing the tolerance range of an organism, we can predict where the organism can live and reproduce. This information can be used to manage habitats, protect endangered species, and predict the impact of environmental changes on organisms. Conclusion Liebig's Minimum Law and Shelford's Law of Tolerance are two basic principles in ecology that explain how environmental factors affect the life of organisms. These two laws complement each other and provide a robust framework for understanding the distribution and abundance of organisms in nature.