Chapter 12 Solutions — Patterns in Life: Diversity and Classification

Revise, Reflect, Refine

1. 1.
   Meena and Hari observed an animal in their garden. Hari called it an insect while Meena said it was an earthworm. Choose the correct option which confirms that it is an insect.

   • (i) Bilateral symmetrical body
   • (ii) Body with jointed legs
   • (iii) Cylindrical body
   • (iv) Body with little segmentation
2. 2.
   Sponges represent one of the simplest animal body plans. Their bodies lack true tissues and organs. Which feature of sponge cells supports its classification under the animal kingdom?

   • (i) Absence of mitochondria
   • (ii) Ability to photosynthesise
   • (iii) Presence of a cell membrane
   • (iv) Presence of a cell wall
3. 3.
   Observe two different animals in your immediate environment. What features help you distinguish between them? How do these features help place them into different groups?
4. 4.
   How would a scientist justify choosing cellular organisation as a more fundamental characteristic for the basis of classification rather than the presence of xylem and phloem?
5. 5.
   You find an unlabelled slide of a single-celled organism that has a well-defined nucleus and multiple cilia. Which group would it most likely belong to? Give reasons.
6. 6.
   How does the diversity of organisms contribute to the balance and stability of an ecosystem?
7. 7.
   If all unicellular organisms were grouped into a single kingdom, what problems would arise?
8. 8.
   Viruses were studied in earlier classes. Why are they not placed in any of the five kingdoms? Give reasons.
9. 9.
   If you were asked to revise the five kingdom classification, would you create a separate category for viruses or keep them outside the system? Justify your answer and explain what this indicates about the evolving nature of scientific classification.
10. 10.
    Viruses contain genetic material like living organisms but lack cellular organisation. Which features prevent them from fitting into the five kingdom system? What does this tell us about the limitations of classification systems?
11. 11.
    Both pteridophytes and bryophytes lack flowers and seeds, yet they are placed in different groups. Explain this classification using their key features.
12. 12.
    In the classification hierarchy, which group — class or genus — has fewer members but more features in common? Explain your answer.
13. 13.
    A scientist discovers a new organism with the characteristic features of locomotion and autotrophic nutrition. Which character(s) would help the scientist identify the organism belonging to Protista according to the five kingdom classification?
14. 14.
    A researcher identified a unicellular eukaryotic organism as fungi. What identification key would you suggest according to the five kingdom classification to keep a unicellular organism in the Kingdom Fungi?
15. 15.
    During a long-term ecological study, students examined organisms collected from three different environments — a freshwater pond, damp soil near decaying logs and the digestive tract of animals. Scientists recorded only structural, cellular and nutritional features: P: Microscopic; no true nucleus; rigid cell covering; survives high salinity and temperature. Q: Multicellular; filamentous body…