Revision Notes: Five Kingdom Classification | Biology Class 9 ICSE PDF Download

Five Kingdom Classification

Introduction

• A species is a group of organisms that can interbreed and produce fertile offspring. The five kingdom classification system is a way of grouping living organisms based on their characteristics.
• Organisms that are similar in structure or related make up the next level of classification called genus.
• A genus is a group of species that are closely related and share common characteristics. A family is a group of related genera that share certain traits.
• An order is a group of related families, and a class is a group of related orders. A phylum is the largest division in the classification of plants and animals, and it includes classes that share common features.
• Related phyla that share certain characteristics form a kingdom.
• Carolus Linnaeus proposed the Two Kingdom Classification in 1758.
• In this system, living organisms were classified into two broad kingdoms: plants and animals.

Two Kingdom Classification

Characteristics of Various Kingdoms

(i) Kingdom: Monera

• Organisms in this kingdom have a prokaryotic cell structure, which means their cells do not have a distinct nucleus.
• Examples include Bacteria, Cyanobacteria, and Mycoplasma.

(ii) Kingdom: Protista

• Organisms in this kingdom have a well-defined nucleus, and their nuclear material is organized in the form of a linear, double-stranded, and helical DNA along with proteins.
• Examples include Chlamydomonas, Euglena, Amoeba, Paramoecium, and Pandorina.

(iii) Kingdom: Fungi

• Organisms in this kingdom possess a true nucleus and a definite cell wall made of chitin.
• Examples include Mucor, Rhizopus, Puccinia, Ustilago, Albugo, Penicillium, and Aspergillus.

(iv) Kingdom: Plantae

• Organisms in this kingdom have a cell wall made of cellulose, a true nucleus, and membrane-bound cell organelles.
• Examples include Algae, moss, fern, pine, and flowering plants like Hibiscus.

(v) Kingdom: Animalia

• Organisms in this kingdom lack a cell wall and plastids.
• Examples include Earthworm, Sycon, beetle, and toad.

(a) Classification of Kingdom Plantae

(i) Division: Thallophyta/Algae

• Plants have an irregularly shaped, undifferentiated body called thallus.
• They are predominantly aquatic.
• Examples include Nostoc, Oscillatoria, and Chlamydomonas.

(ii) Division: Bryophyta

• The plant body is either in the form of an undifferentiated thallus or leafy erect structures.
• There is no specialized tissue for the conduction of water and other substances.
• Examples include Riccia, Funaria, and Anthoceros.

(iii) Division: Pteridophyta

• The plant body is differentiated into stem, leaves, and roots.
• There are specialized tissues for the conduction of water and other substances.
• Examples include Psilotum, Nephrolepis, and Equisetum.

(iv) Division: Gymnospermae

• These plants bear naked seeds.
• They are usually perennial, evergreen, and woody.
• Examples include Gingko, Pinus, and Gnetum.

(v) Division: Angiospermae

• These plants produce seeds enclosed within fruits.
• They are divided into two classes based on the number of cotyledons: monocots and dicots.
• Examples include Maize, bean, and wheat.

(b) Classification of Kingdom Animalia: Vertebrates and Invertebrates

(i) Vertebrates:

• Fish, frog, lizard, and bird are examples of vertebrates.

(ii) Invertebrates:

• Leech, earthworm, and Sycon are examples of invertebrates.

(c) Division of Phylum Invertebrate

(i) Phylum: Porifera

• Simplest multicellular animals with perforated bodies.
• The body consists of a hollow tube.
• Examples include Sycon and bath sponge.

(ii) Phylum: Coelenterata/Cnidaria

• Have a two-layered body wall enclosing a single cavity for digestion.
• Tentacles near the mouth for catching food.
• Examples include Hydra, jellyfish, sea anemone, and corals.

(iii) Phylum: Platyhelminthes

• Small, soft, flattened, unsegmented worms without a body cavity.
• Examples include liver fluke, tapeworm, and Planaria.

(iv) Phylum: Annelida

• Cylindrical body divided into ring-like segments.
• True body cavity called coelom present.
• Examples include earthworm, leech, and Nereis.

(v) Phylum: Nematoda/Nemathelminths

• Long, cylindrical, unsegmented body without a body cavity.
• Examples include hookworm and Ascaris.

(vi) Phylum: Arthropoda

• The body is segmented with a hard exoskeleton.
• Jointed appendages are present.
• Examples include insects, spiders, and crustaceans.

(i) Animals with Jointed Legs (Phylum Arthropoda)

Characteristics:

• Have jointed limbs, with one pair on some or all body segments.
• Have an exoskeleton made of chitin.
• Lack cilia.

Examples:

• Crayfish
• Crab
• Millipede
• Centipede
• Insects
• Scorpion
• Spider

(ii) Animals with Soft Bodies (Phylum Mollusca)

Characteristics:

• Have a soft, unsegmented body without appendages.
• Protected by a hard, calcareous shell.

Examples:

• Snail
• Slug
• Oyster
• Mussel
• Clam
• Squid
• Octopus

(iii) Spiny-Skinned Animals (Phylum Echinodermata)

Characteristics:

• Body may be spherical, cylindrical, or star-shaped.
• Possess a hard, spiny exoskeleton.
• Body is unsegmented or non-metameric.

Examples:

• Starfish
• Brittle star
• Sea urchin
• Sea cucumber

(iv) Animals with Backbone (Phylum Vertebrata)

(a) Fish (Class Pisces)

Characteristics:

• Cold-blooded animals.
• Have a backbone.

Examples:

• Cartilaginous Fish: Shark, Dogfish, Skate
• Bony Fish: Carp, Roach, Herring, Trout

(b) Amphibians (Class Amphibia)

Characteristics:

• Body divided into head and trunk (no neck).
• Three-chambered heart (two auricles, one ventricle).
• Cold-blooded animals.

Examples:

• Frog
• Toad
• Salamander
• Newt

(c) Reptiles (Class Reptilia)

Characteristics:

• Body divided into head, neck, abdomen, and tail.
• Most have a three-chambered heart (ventricle partially divided).

Examples:

• Lizard
• Snake
• Tortoise
• Turtle
• Crocodile
• Alligator

(d) Birds (Class Aves)

Characteristics:

• Warm-blooded animals.
• Four-chambered heart.

Examples:

• Pigeon
• Sparrow
• Crow
• Duck
• Owl
• Penguin
• Ostrich
• Emu

(e) Mammals (Class Mammalia)

Characteristics:

• Warm-blooded animals.
• Four-chambered heart (two auricles, two ventricles).

Examples:

• Cat
• Dog
• Cow
• Sheep
• Rat
• Bat
• Seal
• Monkey
• Apes
• Humans

Binomial Nomenclature

The binomial nomenclature system was proposed by the Swedish botanist Carolus Linnaeus. This system gives each organism a scientific name consisting of two parts: the genus name and the species name. For example, in the scientific name Homo sapiens , Homo is the genus and sapiens is the species. This helps in identifying and classifying organisms accurately.