Class 9 · ScienceNCERT 2026 Revised Syllabus
Chapter 12: Patterns in Life: Diversity and Classification (0906CH12)
Exploration · Five kingdoms, classification hierarchy, features of major groups.
Chapter code: 0906ch12 · Book: Exploration · Class 9 Science
Find complete NCERT solutions for Class 9 Science, Exploration Chapter 12. Every question has a clear, step-by-step answer for chapter code 0906CH12.
Pause and Ponder(10 questions)
1
If many organisms share common features, could they also share a common ancestry?
School Level Solution
Ans.
Shared features can provide evidence that organisms inherited traits from a common ancestor. Scientists compare multiple structural, developmental and genetic features rather than relying on one similarity alone.
2
How can a single-celled organism carry out all its life processes when billions of cells are required to perform similar functions in multicellular organisms like us?
School Level Solution
Ans.
A single cell can carry out nutrition, respiration, excretion, growth and reproduction because it contains the necessary cellular structures and molecular machinery. In multicellular organisms, specialised cells divide these functions among tissues and organs.
3
Which plant features reduce their dependence on water but still require moist conditions?
School Level Solution
Ans.
Vascular tissue, protective body surfaces and seeds helped plants live farther from water. However, groups such as bryophytes and pteridophytes still require moisture/free water for reproduction.
4
Why do taller plants need specialised transport tissues?
School Level Solution
Ans.
In taller plants, roots and leaves are far apart. Xylem transports water and minerals upward and phloem transports food from photosynthetic tissues to other parts over long distances.
5
How do seeds and fruits affect where and how plants can survive?
School Level Solution
Ans.
Seeds protect the embryo and often contain stored food; fruits can aid seed protection and dispersal. Dispersal by wind, water, animals or other mechanisms lets plants reach new habitats and reduces competition with the parent plant.
6
An earthworm (annelida) and a beetle (arthropoda), both have segmented bodies but the beetle has a hard external skeleton. How does the beetle’s external skeleton help it survive?
School Level Solution
Ans.
The beetle’s hard external skeleton protects against injury, reduces water loss and provides a rigid surface for muscles to act on. These features are especially useful in dry, exposed terrestrial habitats.
7
Does the term “biodiversity” relate only to the variety of organisms, or does it encompass other elements?
School Level Solution
Ans.
Biodiversity is broader than simply counting species. It includes diversity within species (genetic diversity), between species, and among ecosystems.
8
If you find a new organism in a pond, what features will you observe to classify it and why?
School Level Solution
Ans.
Useful observations include whether it is prokaryotic/eukaryotic, unicellular/multicellular, its mode of nutrition, cell wall, body organisation, reproduction and other structural/genetic features. These criteria allow comparison with known groups.
9
Why do genetic studies provide deep information about living beings?
School Level Solution
Ans.
Genes are inherited. Comparing DNA sequences can reveal genetic similarity, variation and evolutionary relationships, including relationships that may not be obvious from external appearance.
10
How can changes in climate affect biodiversity?
School Level Solution
Ans.
Changes in temperature, rainfall, sea level and extreme events can alter habitats and food availability. Species may shift ranges or breeding times; species unable to adapt or move can decline or become extinct, reducing biodiversity.
Activities — How to Do(4 questions)
1
Activity 12.4 (bacteria and cyanobacteria slides): observe permanent slides under the microscope and compare with Fig. 12.6. What should you look for?
School Level Solution
Ans.
Both show very small cells without a defined nucleus or membrane-bound organelles. Cyanobacteria may appear as chains/filaments (sometimes greenish); bacteria as rods, spheres or spirals. Match shapes with Fig. 12.6 and note the prokaryotic plan.
2
Activity 12.5 (hay infusion): soak grass/straw in pond water in a muslin-covered bottle for a week, then examine a drop under the microscope. What moving organisms do you expect?
School Level Solution
Ans.
The infusion breeds bacteria, which feed protists: slipping Paramecium (cilia), crawling Amoeba (pseudopodia), green whipping Euglena (flagellum). Record shape and movement of each — a living sample of Kingdom Protista.
3
Activity 12.6 (bryophytes): observe moss-like patches with a hand lens, then a wet mount under the dissecting microscope. How do they differ from ordinary leaves?
School Level Solution
Ans.
Bryophytes form soft green cushions with rhizoids instead of roots and no veins, flowers or seeds; their leaflets are often one cell thick and translucent. Ordinary leaves are larger, veined organs of vascular plants — a different grade of organisation.
4
Activity 12.9 (plant groups table): for Thallophyta, Bryophyta, Pteridophyta, Gymnosperms and Angiosperms, fill Table 12.3 with one survival advantage and one challenge each. What should the table show?
School Level Solution
Ans.
Thallophyta: simple, fast-spreading ↔ no land adaptations. Bryophyta: first land plants ↔ need water for reproduction. Pteridophyta: vascular tissue ↔ still spore-dependent. Gymnosperms: naked seeds, woody ↔ slow reproduction. Angiosperms: flowers/fruits, fast ↔ dominant competitors.