The question asks about a significant limitation of R.H. Whittaker's five-kingdom classification system. We need to identify which group of organisms or entities was not adequately accommodated or classified within this system.
Correct Option: A) Acellular entities such as viruses and viroids, and symbiotic associations such as lichens
The question asks to identify the scientist who proposed the three-domain system of classification (Archaea, Bacteria, and Eukarya) based on ribosomal RNA (rRNA) sequences, which refined the earlier five-kingdom system.
C) Carl Woese — Carl Woese is credited with proposing the three-domain system of classification (Archaea, Bacteria, and Eukarya) in 1977, based on differences in ribosomal RNA (rRNA) sequences. This system provided a more accurate phylogenetic understanding of life.
The question asks about the classification of lichens within the five-kingdom system. Lichens are a symbiotic association of an alga (or cyanobacterium) and a fungus. Understanding the nature of this symbiotic relationship is key to determining their classification.
Correct Option: B) A unique symbiotic association studied separately, rather than being assigned wholly to a single kingdom
This option correctly recognizes that lichens are a special case due to their composite nature. They are studied as a distinct symbiotic entity because they represent an interaction between two different organisms, each belonging to a different kingdom (fungus to Fungi, alga potentially to Protista or Plantae). Assigning them wholly to one kingdom would misrepresent their biological complexity and the contributions of both partners.
The question asks to identify which factor is NOT a basis for Whittaker's five-kingdom classification. We need to recall the key criteria used by R.H. Whittaker in 1969 to classify living organisms into five kingdoms.
Correct Option: D) The particular geographical location where an organism happens to be found
The question asks for the fundamental criterion that distinguishes Kingdom Monera from the other four kingdoms (Protista, Fungi, Plantae, Animalia). This requires understanding the basic characteristics of Monera and how they differ from eukaryotic organisms.
B) Absence of a true, membrane-bound nucleus (i.e., its prokaryotic cellular organisation). This is the most fundamental distinction. Monerans are prokaryotes, meaning their cells lack a membrane-bound nucleus and other membrane-bound organelles. All other four kingdoms (Protista, Fungi, Plantae, Animalia) consist of eukaryotes, which possess a true nucleus.
The question asks about the primary distinction organisms are classified by when using 'mode of nutrition' as a basis. This requires understanding the fundamental ways organisms obtain their food.
Correct Option: C) Autotrophic (self-nourishing, e.g., through photosynthesis) or heterotrophic (depending on other organisms for food)
This option perfectly describes the two main modes of nutrition that form the basis for classifying organisms based on how they obtain food. Autotrophs produce their own food, while heterotrophs consume other organisms.