Merits:

- The separation of prokaryotes as a different kingdom is useful and fits into the contemporary understanding of various organisms.

- This classification is helpful in understanding the progression and development of cellular organization and mode of nutrition.

- This classification remains in par with and supports the theory of evolution by Darwin.

Demerits:

- The classification of kingdoms Monera and Protista are problematic. For one both the kingdoms include organisms with and without cell wall and ones that are autotrophic and heterotrophic.

- Viruses do not get a proper classification.

- Slime moulds, in spite of being considerably different from the rest of its counterparts in the kingdom, have been classified under Protista.

-  Certain organisms under Protista are not eukaryotic, rather mesokaryotic..

Merit and Demerits of Whittaker's Classification

Whittaker's classification is a classification of living organisms based on five kingdoms. This classification system was proposed by Robert Whittaker in 1969. The five kingdoms are Monera, Protista, Fungi, Plantae, and Animalia. The system was widely accepted and used for many years, but it has some merits and demerits.

Merits of Whittaker's Classification

1. Comprehensive: Whittaker's classification system is a comprehensive system that includes all living organisms. It divides the organisms into five kingdoms based on their characteristics.

2. Simple: The classification system is straightforward and easy to understand. It is easy to teach and learn.

3. Flexible: The system is flexible and allows for the inclusion of new organisms that are discovered. It is not rigid and can be modified as needed.

4. Reflects Evolutionary Relationships: The classification system reflects the evolutionary relationships between organisms. The system reflects the evolutionary history of the organisms.

Demerits of Whittaker's Classification

1. Oversimplification: The classification system oversimplifies the complex relationships between organisms. It does not take into account the complexity of the relationships between organisms.

2. Ambiguity: The classification system is ambiguous and can lead to confusion. The boundaries between the different kingdoms are not clear, and there is often overlap between the kingdoms.

3. Lack of Detail: The classification system lacks detail and does not provide enough information about the organisms. It does not provide enough information about the characteristics of the organisms.

4. Ignores Molecular Data: The classification system does not take into account molecular data. The system is based on the observable characteristics of the organisms and does not consider the molecular data.

In conclusion, Whittaker's classification system has both merits and demerits. It is a comprehensive and simple system that reflects the evolutionary relationships between organisms. However, it oversimplifies the complex relationships between organisms, is ambiguous, lacks detail, and ignores molecular data.