ICSE 9 Biology Five Kingdom Short

⚡ Quick Revision : The Five Kingdom System

1. Introduction to Taxonomy

Taxonomy is the branch of biology dealing with the identification, naming, and classification of organisms. Carolus Linnaeus is known as the "Father of Taxonomy."

• ✔ The modern Five Kingdom Classification was proposed by Robert H. Whittaker (1969).

2. Basis of Whittaker's Classification

Whittaker used five major criteria to group organisms. In ICSE, these are often asked as short notes:

• A. Complexity of Cell Structure: Prokaryotic vs. Eukaryotic cells.
• B. Complexity of Organism: Unicellular vs. Multicellular.
• C. Mode of Nutrition: Autotrophic (Plants), Absortive (Fungi), or Ingestive (Animals).
• D. Lifestyle: Producers, Consumers, or Decomposers.
• E. Phylogenetic Relationships: Evolutionary history of the organism.

3. Hierarchy of Classification

Organisms are classified into categories ranging from the most general to the most specific:

Rank	Memory Hook (Mnemonics)
Kingdom	Kings
Phylum (or Division)	Play
Class	Chess
Order	On
Family	Fine
Genus	Green
Species	Square

Term Card

Binomial Nomenclature: A two-name system for every organism (Genus + species). Rules: Genus starts with a Capital letter, species with a small letter, and both must be italicized or underlined.

❌ Don't Confuse:

The term "Phylum" is used for animals, whereas the term "Division" is used for plants in the classification hierarchy.

⚡ Quick Revision : Kingdom Monera & Kingdom Protista

1. Kingdom Monera (The Prokaryotes)

This kingdom includes the most primitive organisms on Earth. They are the only kingdom made of Prokaryotic cells.

• ✔ Cell Structure: Unicellular; lack a defined nucleus and membrane-bound organelles (like mitochondria).
• ✔ Genetic Material: Circular DNA called a nucleoid lies naked in the cytoplasm.
• ✔ Examples: Bacteria, Cyanobacteria (Blue-green algae), Anabaena.

2. Kingdom Protista (The Unicellular Eukaryotes)

This kingdom acts as a link between Monera and the multicellular kingdoms. They are the simplest Eukaryotic organisms.

• ✔ Cell Structure: Mostly unicellular; have a well-defined nucleus and organelles.
• ✔ Locomotion: Use Pseudopodia (Amoeba), Cilia (Paramecium), or Flagella (Euglena).
• ✔ Nutrition: Can be Autotrophic (Euglena) or Heterotrophic (Amoeba).

3. Key Comparison: Monera vs. Protista

Feature	Kingdom Monera	Kingdom Protista
Cell Type	Prokaryotic	Eukaryotic
Nucleus	Absent (Incipient)	Present (True nucleus)
Organelles	Absent	Present

Exam Insight: Euglena

Euglena is a unique protist. It has chloroplasts (plant-like) but can also ingest food when light is absent (animal-like). It is often called a "link" between plants and animals.

❌ Don't Confuse:

Do not think all unicellular organisms are in Monera. If it has a nucleus, it must be in Protista.

⚡ Quick Revision : Kingdom Fungi & Kingdom Plantae

1. Kingdom Fungi (The Saprotrophs)

Fungi were originally grouped with plants, but they lack chlorophyll and cannot perform photosynthesis. They are the great recyclers of the ecosystem.

• ✔ Structure: Body is made of thread-like structures called Hyphae (collectively called Mycelium).
• ✔ Cell Wall: Made of a tough carbohydrate called Chitin (not cellulose).
• ✔ Nutrition: Saprophytic (feeding on dead matter) or Parasitic. Food is stored as Glycogen.
• ✔ Examples: Mushroom (Agaricus), Yeast (unicellular), Bread Mold (Rhizopus).

2. Kingdom Plantae (The Multicellular Autotrophs)

This kingdom contains multicellular eukaryotes that have chlorophyll and produce their own food through photosynthesis.

• ✔ Cell Wall: Rigid and made of Cellulose.
• ✔ Nutrition: Autotrophic. Food is stored as Starch.
• ✔ Sub-groups: Thallophyta (Algae), Bryophyta (Mosses), Pteridophyta (Ferns), Gymnosperms, and Angiosperms.

3. Distinguishing: Fungi vs. Plants

Feature	Kingdom Fungi	Kingdom Plantae
Chlorophyll	Absent	Present
Cell Wall	Chitin	Cellulose
Stored Food	Glycogen	Starch

Technical Term: Hyphae

Individual fungal filaments are Hyphae. A dense network of these filaments is a Mycelium. This structure allows fungi to penetrate deep into their food source to absorb nutrients.

❌ Don't Confuse:

Yeast is a fungus but it is unicellular. Most other fungi are multicellular. However, Yeast is still in Kingdom Fungi because of its cell wall and nutrition mode.

⚡ Quick Revision : Kingdom Animalia (Invertebrates - Part A)

1. General Characteristics of Animalia

Animals are the most diverse kingdom. They are Multicellular Eukaryotes with a few defining features:

• ✔ No Cell Wall: Unlike plants and fungi, animal cells have only a plasma membrane.
• ✔ Nutrition: Heterotrophic (Ingestive/Holozoic). They eat and then digest food internally.
• ✔ Locomotion: Most show active movement to find food or mates.

2. The Lower Invertebrates

Phylum	Key Features	Examples
Porifera	Pore-bearing; stationary; canal system for water flow.	Sycon, Spongilla
Cnidaria	Stinging cells (cnidoblasts); radial symmetry; sac-like body.	Hydra, Jellyfish
Platyhelminthes	Flatworms; dorso-ventrally flattened; mostly parasitic.	Tapeworm, Liver fluke
Nematoda	Roundworms; cylindrical body; unsegmented.	Ascaris, Wuchereria

Biological Reasoning

Question: Why are Tapeworms called endoparasites?
Answer: Because they live inside the host's intestine and absorb pre-digested food directly through their body surface, lacking a digestive system of their own.

❌ Don't Confuse:

Radial Symmetry (Cnidaria) means the body can be divided into identical halves by any plane passing through the center. Bilateral Symmetry (Platyhelminthes onwards) means it can only be divided by one specific plane.

⚡ Quick Revision : Higher Invertebrates

1. Phylum Arthropoda (The Largest Phylum)

Arthropods make up over 80% of all known animal species. Their name means "Jointed Legs."

• ✔ Exoskeleton: Tough outer covering made of Chitin (same material as fungal cell walls).
• ✔ Body Regions: Usually divided into Head, Thorax, and Abdomen.
• ✔ Examples: Cockroach, Butterfly, Prawn, Scorpion, Spider.

2. Other Higher Invertebrate Phyla

Phylum	Key Distinguishing Features	Examples
Annelida	Metamerically segmented body; true body cavity (coelom).	Earthworm, Leech
Mollusca	Soft body; usually protected by a calcareous shell; muscular foot.	Snail, Octopus, Pila
Echinodermata	Spiny-skinned; water vascular system; radial symmetry in adults.	Starfish, Sea Urchin

Term Card: Molting (Ecdysis)

Since the chitinous exoskeleton of arthropods does not grow with the animal, they must periodically shed it and grow a new one. This process is called Molting.

❌ Don't Confuse:

Insects have 3 pairs of legs, while Arachnids (spiders/scorpions) have 4 pairs. Both are Arthropods, but they belong to different classes!

⚡ Quick Revision : Phylum Chordata (Vertebrates)

1. What defines a Chordate?

All vertebrates belong to Phylum Chordata. At some stage of their life, they possess a Notochord (which usually becomes the vertebral column or "backbone" in adults).

2. Classification of Vertebrates

Class	Skin & Respiration	Heart Chambers	Examples
Pisces (Fish)	Scales; Gills	2-Chambered	Rohu, Shark
Amphibia	Moist skin; Lungs/Skin	3-Chambered	Frog, Toad
Reptilia	Dry scales; Lungs	3-Chambered*	Lizard, Snake
Aves (Birds)	Feathers; Lungs	4-Chambered	Pigeon, Ostrich
Mammalia	Hair; Lungs	4-Chambered	Bat, Whale, Human

*Crocodiles are reptiles but have a 4-chambered heart.

3. Thermal Regulation

• Poikilothermic (Cold-blooded): Body temperature changes with the surroundings.
  Includes: Pisces, Amphibia, Reptilia.
• Homeothermic (Warm-blooded): Maintain a constant body temperature regardless of environment.
  Includes: Aves, Mammalia.

Unique Mammalian Features

Mammals are distinguished by the presence of Milk-producing Mammary glands, external ears (Pinna), and a Diaphragm separating the chest and abdomen.

❌ Don't Confuse:

Whales and Bats are Mammals, not fish or birds! Whales give birth to live young and nurse them; Bats have fur and mammary glands.