Question

Five kingdom system of classification suggested by R.H. Whittaker is not based on

• A. presence or absence of a well defined nucleus
• B. mode of reproduction
• C. mode of nutrition
• D. complexity of body organisation.

Answer 1

The Correct Option is A

The question asks about the characteristic that is not a basis for R.H. Whittaker's five kingdom classification system. Let's examine the importance and contribution of each option to the classification system:

1. Presence or absence of a well-defined nucleus:

   The presence or absence of a well-defined nucleus is primarily used to distinguish between prokaryotic and eukaryotic cells. This characteristic is fundamental in the initial division between the kingdoms Monera (prokaryotic organisms) and all other kingdoms (eukaryotic organisms). However, Whittaker's system focuses on other criteria such as mode of nutrition, complexity, etc., within eukaryots.

2. Mode of reproduction:

   While the reproduction method aids species identification within kingdoms, it is not a primary criterion in Whittaker's framework to distinguish major kingdoms. The emphasis is more on morphological and nutritional characteristics.

3. Mode of nutrition:

   This is a primary factor in Whittaker’s classification, distinguishing kingdoms such as Plantae (autotrophs) and Fungi (heterotrophs). Here, the method of obtaining food (photosynthesis, absorption, ingestion) defines specific kingdoms.

4. Complexity of body organization:

   This factor pertains to the structural complexity of the organism (unicellular or multicellular). It is indeed vital in determining the classification into kingdoms, as it helps in distinguishing between simple organisms like Protists and complex organisms like Animals and Plants.

From the analysis above, we conclude that the presence or absence of a well-defined nucleus is not the basis by itself for dividing the eukaryotic kingdoms in Whittaker's system, as this is more of a prokaryote vs. eukaryote differentiation rather than detailed kingdom classification. Therefore, the correct answer is:

Correct Answer: presence or absence of a well-defined nucleus