Biodiversity is the variety of all living organisms on Earth and the complex interactions they share with each other and their environment. It helps us understand how different species coexist, adapt, and contribute to the balance of ecosystems.
In this chapter, we first explore the concept and importance of Biodiversity, then learn about Taxonomic Ranks, which provide a structured way to classify and organize living organisms based on their shared characteristics. We also study the History of Classification to understand how scientists in the past categorized organisms and how modern methods have refined this system.
Finally, we examine the Domains of Living Organisms, which divide life into three major groups – Bacteria, Archaea, and Eukarya – based on their fundamental characteristics. Understanding these domains helps us appreciate the evolutionary relationships and the diversity of life forms on our planet.
By the end of this chapter, students will have a clear understanding of the variety of life, the patterns that govern it, and the scientific methods used to study and classify organisms.
Class 9 Biology Chapter 2 MCQs – Biodiversity
1. Which of the following statements is NOT related to bacteria?
a) Do not have a nucleus
b) Cell wall made of peptidoglycan
c) Most are heterotrophic
d) Have chlorophyll in their chloroplasts
Answer: d) Have chlorophyll in their chloroplasts ✅
2. Which kingdom includes organisms that are eukaryotic, often unicellular, and heterotrophic?
a) Archaea
b) Protista
c) Fungi
d) Plantae
Answer: b) Protista ✅
3. What does the term ‘biodiversity’ refer to?
Options:
a) The number of different organisms in a given area
b) The diversity of species in the oceans
c) The abundance of a single species in an ecosystem
d) The variety of geographical regions
4. International Biodiversity Day is celebrated on which date?
a) May 22nd
b) March 22nd
c) June 5th
d) April 22nd
Answer: a) May 22nd ✅
5. Which taxonomic rank was added to the Linnaean system in 1977?
a) Family
b) Domain
c) Order
d) Kingdom
6. In the Five-Kingdom Classification System, which kingdom includes organisms like bacteria and archaea?a) Protista
b) Monera
c) Fungi
d) Plantae
Answer: b) Monera ✅
7. What is the major difference between Kingdom Protista and Kingdom Fungi?
a) Protists are multicellular while fungi are unicellular
b) Fungi are autotrophs, while protists are heterotrophs
c) Fungi absorb nutrients from decaying matter, while protists ingest food or photosynthesize
d) Protists have chitin in their cell walls, while fungi do not
Answer: c) Fungi absorb nutrients from decaying matter, while protists ingest food or photosynthesize ✅
Class 9 Biology Chapter 2 short questions – Biodiversity
Question 1: What are the basic differences between Archaea and Bacteria?
Answer:
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Archaea have cell walls made of polypeptides and proteins, while bacteria have peptidoglycan in their cell walls.
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Archaea can survive in extreme environments, while bacteria are found in a wide range of habitats.
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Archaea’s rRNA is more similar to eukaryotes than bacteria.
Question 2: What are the shortcomings of the three-kingdom classification system?
Answer:
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The three-kingdom system does not account for the vast diversity of organisms, especially unicellular eukaryotes and viruses.
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It groups some organisms like fungi and bacteria together, despite significant differences in their structure and nutrition.
Question 3: How does biodiversity support ecosystem stability? Give two examples.
Answer:
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Biodiversity maintains food web balance and nutrient cycles.
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Example 1: Various plants and herbivores help maintain vegetation.
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Example 2: Predators control herbivore populations, preventing overgrazing.
Question 4: What is the primary difference between Domain Archaea and Domain Bacteria?
Answer:
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Cell Wall Composition: Archaea have unique cell walls and membranes made of proteins and polysaccharides, and they do not contain peptidoglycan, whereas bacteria have cell walls made of peptidoglycan.
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rRNA and Evolutionary Similarity: The rRNA sequences of Archaea are more similar to eukaryotes than to bacteria.
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Habitat Adaptation: Archaea often live in extreme environments, while bacteria are found in a wide variety of habitats
Question 5: What is the significance of binomial nomenclature?
Answer:
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Binomial nomenclature provides a standard and universal way to name organisms.
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It ensures that each species has a unique and universally accepted scientific name.
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This system avoids confusion caused by common names.
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These notes include important MCQs, short questions, and detailed answers from Class 9 Biology Chapter 2 – Biodiversity. Perfect for exam preparation and quick revision.