Five-kingdom classification

Because the natural world is so complex, the study of science involves the organization of items into smaller groups based on interaction or interdependence. These groups are called systems. Examples of organization are the periodic table of elements and the five-kingdom classification scheme for living organisms. Examples of systems are the solar system, cardiovascular system, Newton s laws offeree and motion, and the laws of conservation. 

Some biologists prefer a three-domain classification scheme— Bacteria (eubacteria), Archaea (archaebacteria), and Eukarya (eukaryotes)—to the five-kingdom classification (Figure 1.19). The basis for this preference is the emphasis on biochemistry as the basis for classification. 

In the five-kingdom classification scheme, prokaryotes have a kingdom to themselves (Monera). The remaining four kingdoms—protists, fungi, plants, and animals—consist of eukaryotes. 

Recall List the three domains into which living organisms are divided, and indicate how this scheme differs from the five-kingdom classification scheme. 

Linnaeus divided all organisms into two kingdoms, Plant and Animal. This system persisted for several hundred years, even though increasing numbers of organisms did not fit well within either of these categories. In 1969, Dr. Robert Whittaker of Cornell University proposed a five-kingdom system of classification (see Table 5.1). 

Table 3.1 Five-kingdom system of classification (after Whittaker, 1969, in Campbell et al, 1999).

Currently, the most widely accepted system of classification of organisms is the five-kingdom system (Table 3-3) of Whittaker (1969). Prokaryotic organisms are placed in the Kingdom Monera, which includes the bacteria and cyanobacteria whose... 

A five-kingdom system takes into account the differences between prokaryotes and eukaryotes, and it also provides classifications for eukaryotes that appear to be neither plants nor animals. 

Members of the five different kingdoms of the classification system of living organisms often differ in their basic life functions. Here we compare and analyze how members of the five kingdoms obtain nutrients, excrete waste, and reproduce. 

The third edition of Five Kingdoms by Margulis and Schwartz (1998) gives an excellent presentation of the evolution of the concepts underlying various systems for the classification of living organisms. 

Fitch uses the combination of the LTV and the affordability measure for a loan in order to arrive at a base case default probability for any particular borrower in a particular rating test. In the United Kingdom, the income multiple has traditionally been used as the measure of loan affordability, and Fitch places loans in one of five classifications based on this measure (Exhibit 11.4). 

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