Diversity of Living World

The Diversity of Living Organisms explores the vast variety of life forms on Earth, from microscopic bacteria to complex plants and animals. This chapter covers the importance of classifying organisms into different categories to understand their relationships and characteristics. It introduces classification systems like the two-kingdom and five-kingdom models and highlights the key features of each kingdom, providing a foundation for further study in biology.

1. What is Diversity in the Living World?

  • Diversity refers to the wide variety of living organisms on Earth, including animals, plants, and microorganisms that inhabit different environments such as land, water, ice, and deserts.
  • Each organism has unique features like different structures, functions, and genetic codes (DNA).
  • Biodiversity describes the range of life forms and is often highest in regions with many species, such as rainforests, known as mega-biodiversity areas.

2. Why Do We Classify Living Things?

To make sense of the many different organisms, scientists use classification to group them based on their similarities and differences.

Factors for Classification:

  • Presence of Nucleus: Whether cells have a nucleus.
  • Body Design: Whether organisms are single-celled or multicellular.
  • Food Production: How they get their food—making it themselves (plants) or consuming other organisms (animals).
  • Body Organization: How their body parts are arranged.

3. Classification Systems

  • Two-Kingdom Classification:
    • Introduced by Carolus Linnaeus.
    • Divides organisms into Plants and Animals.
  • Five-Kingdom Classification:
    • Introduced by Robert Whittaker.
    • Divides organisms into five kingdoms:
      • Monera: Bacteria and similar organisms.
      • Protista: Single-celled organisms like amoebas.
      • Fungi: Organisms like mushrooms and yeast that decompose dead matter.
      • Plantae: Plants that perform photosynthesis.
      • Animalia: Animals that consume other organisms.

4. Hierarchy of Classification

Organisms are organized into groups from broad to specific:

  1. Kingdom
  2. Phylum
  3. Class
  4. Order
  5. Family
  6. Genus
  7. Species

5. Characteristics of the Five Kingdoms

  • Kingdom Monera:
    • Unicellular, no true nucleus.
    • Examples: Bacteria, Cyanobacteria.
  • Kingdom Protista:
    • Unicellular with a nucleus.
    • Examples: Amoeba, Paramecium.
  • Kingdom Fungi:
    • Multicellular, cell wall made of chitin.
    • Examples: Yeast, Mushrooms.
  • Kingdom Plantae:
    • Multicellular, cell walls made of cellulose, performs photosynthesis.
    • Subdivided into groups like Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, and Angiosperms.
    • Examples: Mango trees, Ferns.
  • Kingdom Animalia:
    • Multicellular, no cell walls, consumes other organisms.
    • Examples: Earthworms, Hydra.

6. Evolution and Classification

  • Evolution explains how organisms change over time and helps us understand their classification and relationships.

Conclusion

Understanding the diversity of living organisms helps us appreciate the complexity of life on Earth. Classification is a key tool for organizing and studying this vast diversity.

For more detailed explanations and practice questions, you can refer to the FAQs provided in the exam guide on the following pages.

Next:

  1. SAQs – Diversity of Living World
  2. VSAQs – Diversity of Living World

Intermediate 1st Year Zoology

  1. Diversity Of Living World
  2. Structural Organization In Animals
  3. Animal Diversity-1
  4. Animal Diversity-2
  5. Locomotion And Reproduction
  6. Biology In Human Welfare
  7. Periplaneta Americana
  8. Ecology And Environment

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