Five Kingdom Classification

1. Complexity of Cell Structure: Whether the organism is Prokaryotic (primitive, lacking nuclear membrane) or Eukaryotic (true membrane-bound nucleus).
   2. Complexity of Body Organization: Whether the organism is Unicellular (single-celled) or Multicellular (with tissues or organs).
   3. Mode of Nutrition: Whether Autotrophic (photosynthetic), Absorptive Heterotrophic (saprophytic decomposition), or Ingestive Holozoic.
   4. Ecological Role (Lifestyle): Producers (plants), Decomposers (fungi/bacteria), or Consumers (animals).

• (i) Kingdom Monera:
1. Strictly Prokaryotic organisms lacking a nuclear envelope, nucleolus, and membrane-bound organelles.
2. Possess a rigid cell wall composed of peptidoglycan (amino sugars).
Example: Bacteria (Escherichia coli), Blue-green algae (Nostoc).
• (ii) Kingdom Fungi:
1. Eukaryotic, non-photosynthetic organisms possessing cell walls made of Chitin.
2. Mode of nutrition is strictly Heterotrophic (Absorptive Saprotrophs), secreting enzymes to digest organic matter externally.
Example: Yeast, Bread mould (Rhizopus), Mushroom (Agaricus).

• Like animal amphibians (frogs) that live on land but must return to water to breed, Bryophytes (mosses and liverworts) live on moist terrestrial soil but depend strictly on external water for sexual reproduction.
• Their flagellated male gametes (antherozoids) must swim through a film of surface water to reach the archegonium and fertilize the egg cell.
• Without water, fertilization is impossible.

• Gymnosperms:
1. Seeds are "Naked" (not enclosed inside a fruit); ovules are exposed on the scales of woody cones.
2. Do not produce true flowers or fruits.
Example: Pine (Pinus), Cycas.
• Angiosperms:
1. Seeds are "Enclosed" inside a protective fruit developed from a fertilized ovary.
2. Produce true flowers with stamens and carpels.
Example: Mango (Mangifera indica), Pea, Rose.

• Rules of Binomial Nomenclature (Linnaeus):
1. Every scientific name consists of two parts: the Generic Name (Genus) followed by the Specific Epithet (Species).
2. The Genus name begins with a Capital letter, while the Species name begins with a small letter.
3. In printed text, the name must be set in Italics; when handwritten, the Genus and Species must be underlined separately.
• Examples:
- Human: Homo sapiens
- Mango: Mangifera indica

• Distinguishing Feature: Unicellular eukaryotic organisms having a true membrane-bound nucleus and specialized organelles.
• Autotrophic Protist: Euglena (contains chloroplasts and photosynthesizes in light) or Diatoms.
• Heterotrophic Protist: Amoeba or Paramecium (ingests food by phagocytosis).

• (i) Number of Cotyledons: Monocots have a single cotyledon (scutellum); Dicots have two cotyledons.
• (ii) Leaf Venation: Monocots have Parallel venation (veins run parallel); Dicots have Reticulate venation (veins form a network).
• (iii) Root System: Monocots possess a Fibrous root system; Dicots possess a Taproot system.

• Viruses are non-cellular (acellular) biological entities.
• They lack protoplasm, cell membranes, ribosomes, and independent metabolic enzyme systems.
• Outside a living host, they exist as inert, crystalline nucleoprotein particles that exhibit zero characteristics of life.
• Because Whittaker's classification is based on cellular organization (prokaryote vs eukaryote), viruses cannot fit into any of the five kingdoms.