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Biological Classification - Five kingdom classification

Grade 11CBSEBiology

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

The Five Kingdom Classification was proposed by R.H. Whittaker in 19691969.

The five kingdoms are: Monera, Protista, Fungi, Plantae, and Animalia.

The main criteria for classification include: Cell structure (Prokaryotic vs Eukaryotic), Thallus organization, Mode of nutrition, Reproduction, and Phylogenetic relationships.

Kingdom Monera: Includes all prokaryotes. Cell walls are non-cellulosic, composed of polysaccharides and amino acids. They exhibit both autotrophic (chemosynthetic and photosynthetic) and heterotrophic (saprophytic or parasitic) modes of nutrition.

Kingdom Protista: Includes all unicellular eukaryotes. This kingdom forms a link between Monera and the other three multicellular kingdoms. Some possess flagella or cilia for movement.

Kingdom Fungi: Heterotrophic organisms (mostly saprophytic). Their cell walls are composed of chitin (a polymer of NN-acetylglucosamine) and polysaccharides. Examples include AgaricusAgaricus and SaccharomycesSaccharomyces.

Kingdom Plantae: Includes all eukaryotic chlorophyll-containing organisms. Their cell wall is primarily made of cellulose. They follow an autotrophic mode of nutrition via photosynthesis: 6CO2+6H2OC6H12O6+6O26CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2.

Kingdom Animalia: Multicellular eukaryotes that lack cell walls. They are heterotrophic and typically ingest food (holozoic nutrition).

Viruses, Viroids, Prions, and Lichens are not included in Whittaker's Five Kingdom System of classification.

📐Formulae

6CO2+12H2OChlorophyllSunlightC6H12O6+6H2O+6O26CO_2 + 12H_2O \xrightarrow[Chlorophyll]{Sunlight} C_6H_{12}O_6 + 6H_2O + 6O_2 \uparrow

Cell Wall (Fungi)=Chitin+Polysaccharides\text{Cell Wall (Fungi)} = \text{Chitin} + \text{Polysaccharides}

Cell Wall (Monera)=Polysaccharide+Amino Acids (Peptidoglycan)\text{Cell Wall (Monera)} = \text{Polysaccharide} + \text{Amino Acids (Peptidoglycan)}

💡Examples

Problem 1:

Which criteria did R.H. Whittaker use to distinguish between Kingdom Monera and Kingdom Protista, and which organism among AnabaenaAnabaena and AmoebaAmoeba belongs to which kingdom?

Solution:

Criteria: Cell type (Prokaryotic vs. Eukaryotic). AnabaenaAnabaena belongs to Kingdom Monera; AmoebaAmoeba belongs to Kingdom Protista.

Explanation:

Whittaker separated organisms based on cell complexity. Kingdom Monera contains prokaryotic organisms (lacking a nuclear membrane), such as the cyanobacterium AnabaenaAnabaena. Kingdom Protista contains unicellular eukaryotic organisms (possessing a defined nucleus), such as AmoebaAmoeba.

Problem 2:

Calculate the ratio of Carbon, Hydrogen, and Oxygen atoms in the glucose molecule (C6H12O6C_6H_{12}O_6) produced by organisms in Kingdom Plantae.

Solution:

1:2:11:2:1

Explanation:

In the chemical formula for glucose, C6H12O6C_6H_{12}O_6, the number of atoms are C=6C=6, H=12H=12, and O=6O=6. Dividing by the common factor 66, the empirical ratio is C1H2O1C_1H_2O_1, which is 1:2:11:2:1.

Problem 3:

In the Five Kingdom system, why are fungi no longer classified with plants?

Solution:

Difference in cell wall composition (Chitin vs. Cellulose) and mode of nutrition (Heterotrophic vs. Autotrophic).

Explanation:

Fungi have cell walls made of chitin (C8H13O5NC_8H_{13}O_5N)n_n, whereas plants have cellulosic cell walls. Furthermore, fungi are heterotrophic/saprophytic, while plants are autotrophic and perform photosynthesis.

Five kingdom classification - Revision Notes & Key Diagrams | CBSE Class 11 Biology