Class 9 Biology - Diversity in Living Organisms | Willer Academy

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Class 9 Biology - NCERT Supplement

Chapter 3: Diversity in Living Organisms

Exploring the Tree of Life

Chapter 3: Diversity in Living Organisms - Detailed Notes

1. Introduction to Biodiversity

Key Concept: Biodiversity refers to the variety of life forms found on Earth. It includes diversity at genetic, species, and ecosystem levels.

Why Classify?

Classification helps in studying the diversity of life by grouping organisms based on similarities and differences.

Basis of Classification

Organisms are classified based on characteristics like cell structure, body organization, mode of nutrition, etc.

2. The Five Kingdom Classification

Monera

Prokaryotic, unicellular organisms (e.g., bacteria, cyanobacteria)

Protista

Eukaryotic, mostly unicellular (e.g., amoeba, paramecium, algae)

Fungi

Heterotrophic, eukaryotic organisms (e.g., yeast, mushrooms, mold)

Plantae

Autotrophic, multicellular eukaryotes (e.g., mosses, ferns, flowering plants)

Animalia

Heterotrophic, multicellular eukaryotes (e.g., insects, fish, mammals)

3. Plant Kingdom Divisions

Division Characteristics Examples
Thallophyta Simple plants without differentiation into root, stem, leaves Algae, fungi, lichens
Bryophyta Non-vascular plants with rhizoids Mosses, liverworts
Pteridophyta Vascular plants without seeds Ferns, horsetails
Gymnosperms Naked-seed plants Pine, cycas
Angiosperms Flowering plants with seeds in fruits Rose, wheat, mango

4. Animal Kingdom Phyla

Porifera

Pore-bearing organisms (sponges)

Coelenterata

Hollow-bodied animals (jellyfish, corals)

Platyhelminthes

Flatworms (tapeworms, planaria)

Nematoda

Roundworms with cylindrical bodies

Annelida

Segmented worms (earthworm, leech)

Arthropoda

Jointed legs (insects, spiders, crustaceans)

Mollusca

Soft-bodied animals (snails, octopus)

Echinodermata

Spiny-skinned animals (starfish, sea urchin)

Chordata

Animals with notochord (fish, birds, mammals)

Phylogenetic tree showing evolutionary relationships between major animal groups

5. Binomial Nomenclature

Definition: The system of naming species with two parts: genus (capitalized) and species (lowercase). Developed by Carolus Linnaeus.

Examples: Homo sapiens (Humans)
Panthera tigris (Tiger)
Mangifera indica (Mango tree)

Multiple Choice Questions (20 Questions)

Select the correct answer for each question. Each question carries 1 mark.

1. Which kingdom includes organisms that are prokaryotic and unicellular?
Protista
Fungi
Monera
Plantae
2. Which of the following is NOT a characteristic of chordates?
Notochord
Dorsal nerve cord
Pharyngeal gill slits
Exoskeleton
3. In the five-kingdom classification, who proposed the kingdom Monera?
Carolus Linnaeus
Ernst Haeckel
Robert Whittaker
Carl Woese
4. Which division of plants has seeds not enclosed in fruits?
Angiosperms
Pteridophyta
Gymnosperms
Bryophyta

Test Progress: 0/20 questions answered

Short Answer Questions (5 Questions - 2 Marks Each)

Answer these questions in 30-50 words.

1. What is the basis of the five-kingdom classification?
2. Differentiate between gymnosperms and angiosperms.
3. Why are bryophytes called amphibians of the plant kingdom?
4. What are the main characteristics of arthropods?
5. Explain binomial nomenclature with examples.

Subjective Questions (5 Questions - 5 Marks Each)

Answer these questions in detail (100-150 words).

1. Describe the five-kingdom classification system with characteristics and examples of each kingdom.
2. Explain the major divisions of the plant kingdom along with their distinguishing features.
3. Compare and contrast the characteristics of vertebrates and invertebrates.
4. What is the importance of classification? Discuss the hierarchy of classification groups.
5. Describe the characteristics of chordates and classify them into their major subgroups with examples.

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You have a solid understanding of biological diversity. Keep exploring the amazing variety of life!

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