Class 11 Biology - KERALA
Biological Classification
The chapter Biological Classification in Class 11 Kerala SCERT Biology explores how living organisms are systematically grouped based on shared characteristics. It traces the history of classification from Aristotle's simple morphological groupings to R.H. Whittaker's sophisticated Five Kingdom Classification system, which includes Monera, Protista, Fungi, Plantae, and Animalia. Students learn about the defining features, cell structure, mode of nutrition, and reproduction of each kingdom. Additionally, the chapter covers non-cellular entities like viruses, viroids, and lichens. This is a high-scoring foundational chapter that frequently appears in Kerala Higher Secondary examinations with direct descriptive and comparative questions.
Start Learning FreeKey Concepts
Five Kingdom Classification
Proposed by R.H. Whittaker in 1969, classifying organisms into Monera, Protista, Fungi, Plantae, and Animalia based on cell structure, thallus organization, mode of nutrition, reproduction, and phylogenetic relationships.
Kingdom Monera
Comprises all prokaryotes, mainly bacteria, which show the most extensive metabolic diversity and can be autotrophic or heterotrophic.
Kingdom Protista
Includes single-celled eukaryotes like chrysophytes, dinoflagellates, euglenoids, slime moulds, and protozoans, acting as a link between prokaryotes and multicellular eukaryotes.
Kingdom Fungi
Heterotrophic spore-bearing organisms with cell walls made of chitin, existing mostly as filamentous structures called hyphae that form a network known as mycelium.
Viruses and Viroids
Non-cellular infectious agents that are inert outside a host cell; viruses contain genetic material surrounded by a protein coat, while viroids consist only of a free infectious RNA strand without a protein coat.
Important Formulas
Board Exam Info
In the Kerala SCERT Class 11 Biology public examinations, this chapter typically carries around 4 to 6 marks. Common question types include distinguishing features of the Five Kingdoms, differences between viruses and viroids, economic importance of fungi, and short notes on bacterial nutrition or archaebacteria.
Frequently Asked Questions
Viruses are non-cellular organisms that do not possess a cell structure, metabolism of their own, or independent living characteristics outside a host, which is why Whittaker's system did not classify them.
Viruses are not truly living outside a host cell and lack cellular machinery, hence they do not fit into any of the five cellular kingdoms proposed by Whittaker.
What is the difference between bacteriophages and plant viruses?
Bacteriophages are viruses that infect bacteria and usually have double-stranded DNA, whereas plant viruses typically have single-stranded RNA.
What are lichens and what is their role in nature?
Lichens are symbiotic associations between algae and fungi. They act as very good pollution indicators because they do not grow in sulfur dioxide-polluted areas.
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