BC09 — The Living World & Classification

📖 BC09 · CDS General Knowledge — Biology CDS Level

Classification imposes order on the vast diversity of life — over 8.7 million species. CDS tests the hierarchy of classification (kingdom to species), the five-kingdom system, and binomial nomenclature. These are straightforward memorisation questions.

📌 CDS Focus: Five kingdoms: Monera, Protista, Fungi, Plantae, Animalia; binomial nomenclature introduced by Linnaeus; scientific name of humans = Homo sapiens; viruses are not in any kingdom (acellular); bacteria in Kingdom Monera; smallest taxonomic unit = species. These are direct CDS factual questions.

1. Hierarchy of Classification

Fig. 1 — Taxonomic Hierarchy from Kingdom to Species (Most General to Most Specific)

2. Five Kingdom Classification

KingdomCell TypeNutritionExamples MoneraProkaryote (no nucleus)Autotrophic or HeterotrophicBacteria, Cyanobacteria (Blue-green algae) ProtistaEukaryote, unicellularAutotrophic or HeterotrophicAmoeba, Paramecium, Euglena, Diatoms FungiEukaryote; no chlorophyll; cell wall of chitinHeterotrophic (saprophytic)Mushroom, Yeast, Penicillium, Rhizopus PlantaeEukaryote; cell wall of cellulose; chloroplastsAutotrophic (photosynthesis)All plants: algae, mosses, ferns, flowering plants AnimaliaEukaryote; no cell wall; no chloroplastHeterotrophic (holozoic)All animals: insects, fish, mammals, birds

Binomial Nomenclature — Rules (Linnaeus, 1758):

● Each species gets a two-part Latin name: Genus species
● Genus name starts with a capital letter; species name in lower case
● Both names italicised when printed; underlined when handwritten
● Examples: Homo sapiens (human), Panthera leo (lion), Felis catus (cat), Oryza sativa (rice), Mangifera indica (mango)

📝 CDS PYQs — Living World

Q1. The scientific name of mango is: CDS PYQ

(a) Mangifera indica(b) Indica mangifera(c) Homo sapiens(d) Panthera leo

✔ Answer: (a) Mangifera indica

Mangifera indica is the scientific (binomial) name of mango. Mangifera is the genus (starts with capital M); indica is the species (lower case). Carl Linnaeus introduced this two-name system (binomial nomenclature) in 1758. Scientific names are universal — the same in any language or country. Other important names: Rice = Oryza sativa; Wheat = Triticum aestivum; Lion = Panthera leo; Tiger = Panthera tigris.

Q2. Bacteria are classified under Kingdom: CDS PYQ

(a) Protista(b) Fungi(c) Monera(d) Plantae

✔ Answer: (c) Monera

Kingdom Monera contains all prokaryotic organisms — bacteria and cyanobacteria (blue-green algae). They lack a membrane-bound nucleus and membrane-bound organelles. Bacteria are the most abundant and diverse organisms on Earth. They can be autotrophic (photosynthetic or chemosynthetic) or heterotrophic. Protista = unicellular eukaryotes (like Amoeba); Fungi = eukaryotes with chitin cell wall; Viruses do NOT belong to any kingdom.

🧠 Quick Memory Chart — BC09

📊 Hierarchy

King Philip Came Over For Good Soup
Kingdom→Phylum→Class→Order→Family→Genus→Species
Species = smallest taxonomic unit
Kingdom = largest taxonomic unit
Human: Animalia→Chordata→Mammalia→Primates→Hominidae→Homo→sapiens

🌿 Five Kingdoms

Monera: prokaryotes (bacteria)
Protista: unicellular eukaryotes (Amoeba)
Fungi: chitin wall; saprophytic
Plantae: cellulose wall; autotrophs
Animalia: no cell wall; heterotrophs

📖 Binomial Names

Human: Homo sapiens
Mango: Mangifera indica
Rice: Oryza sativa
Lion: Panthera leo
Introduced by: Linnaeus (1758)

📝 Practice Exercise

E1. Which kingdom contains organisms that are eukaryotic, unicellular, and can be both autotrophic and heterotrophic?

(a) Monera(b) Protista(c) Fungi(d) Plantae

E2. In binomial nomenclature, the scientific name is written as:

(a) Species genus (both lower case)(b) Genus Species (both capitals)(c) Genus species (genus capitalised, species lower case)(d) genus species (both lower case)

Answers:
E1 → (b) Protista [eukaryotic, mostly unicellular; Euglena is both autotrophic (has chlorophyll) and heterotrophic (can absorb food)] | E2 → (c) Genus capitalised, species lower case [e.g., Homo sapiens; both italicised when printed]

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