Start by reviewing these Exploration Class 9 Science Solutions Chapter 12 Patterns in Life Diversity and Classification Question Answer NCERT Solutions to strengthen your knowledge.
Class 9 Science Exploration Chapter 12 Question Answer
Class 9 Science Ch 12 Patterns in Life Diversity and Classification Question Answer
Patterns in Life Diversity and Classification Class 9 Questions and Answers (Exercise)
Revise, Reflect, Refine
Question 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
Solution:
(ii) Insects belong to Arthropoda and have jointed legs. Earthworms have cylindrical, segmented bodies with no jointed legs.
Question 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
Solution:
(iii) Animal cells have a cell membrane but no cell wall. Sponges are animals; they do not photosynthesise, and they do not have cell walls.
Question 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?
Solution:
Two animals, such as a dog and a butterfly, can be distinguished based on several features. The dog has a backbone, fur, and moves by walking, whereas the butterfly has wings, an exoskeleton, and flies. These features help in classification as the dog is a vertebrate (having a backbone), while the butterfly is an invertebrate belonging to the group Arthropoda. Thus, differences in body structure and movement help place them into different groups.
Question 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?
Solution:
Cellular organisation (prokaryote vs eukaryote, unicellular vs multicellular) applies to all living things, including plants, animals, fungi, and bacteria. But xylem and phloem are found only in some plants. So cellular organisation is more fundamental and universal as a basis for classification.
Question 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.
Solution:
It most likely belongs to Kingdom Protista (like Paramecium). It is unicellular; it has a true nucleus (eukaryote), and cilia help it move in water. All these features together point to Kingdom Protista.
Question 6.
How does the diversity of organisms contribute to the balance and stability of an ecosystem?
Solution:
Diversity of organisms ensures that different ecological roles, such as producers, consumers, and decomposers, are fulfilled. Plants produce food and oxygen, animals help in pollination and seed dispersal, and microorganisms decompose dead matter and recycle nutrients. This interdependence maintains ecological balance and increases the stability of ecosystems.
Question 7.
If all unicellular organisms were grouped into a single kingdom, what problems would arise?
Solution:
Unicellular organisms vary greatly as some are prokaryotic while others are eukaryotic. Their modes of nutrition also differ, as some are autotrophic while others are heterotrophic. Grouping them into one kingdom would ignore these fundamental differences. This would make classification meaningless and fail to reflect true evolutionary relationships.
Question 8.
Why are viruses not placed in any of the five kingdoms? Give a reason.
Solution:
Viruses are not truly living. They have no cells, cannot carry out life processes on their own, only become active inside a host cell and have no metabolism. All five kingdoms are made of cells. Since viruses have no cellular organization, they do not fit anywhere in the five-kingdom system.
Question 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.
Solution:
Yes, many scientists suggest viruses deserve their own category since they have genetic material but are acellular. This shows that classification systems are not perfect or permanent, they keep changing as we learn more. Science is always evolving and updating itself based on new discoveries.
Question 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?
Solution:
Viruses lack cellular organization, their own metabolism and the ability to reproduce independently. This tells us that the five kingdom system has limitations as it was designed for cellular life forms. Viruses challenge our very definition of life and show that classification systems need to be flexible.
Question 11.
Both pteridophytes and bryophytes lack flowers and seeds, yet they are placed in different groups. Explain.
Solution:
Even though both bryophytes and pteridophytes do not have flowers or seeds, they are placed in different groups because of important differences in their body structure. Bryophytes are simpler plants that do not have true roots, stems, or leaves and they completely lack vascular tissues like xylem and phloem, which means they cannot transport water and food efficiently to different parts of the plant.
Pteridophytes, on the other hand, are more advanced because they have proper roots, stems and leaves and they also have well-developed vascular tissues that help them transport water and nutrients throughout the plant body. This makes pteridophytes much better adapted to life on land compared to bryophytes. Both still need water for reproduction, but the presence of vascular tissue and true plant organs is the key reason they are classified separately.
Question 12.
In the classification hierarchy, which group, class or genus has fewer members but more features in common? Explain your answer.
Solution:
In the classification hierarchy, genus has fewer members but more features in common. This is because genus is a lower category than class. Organisms in the same genus are closely related and share many similar characteristics, whereas a class includes a larger number of organisms with fewer similarities. Hence, genus is more specific.
Question 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 as belonging to Protista according to the five-kingdom classification?
Solution:
Protista includes unicellular eukaryotic organisms, and the presence of both locomotion and autotrophic nutrition is characteristic of organisms like Euglena, which belongs to this kingdom. The unicellular and eukaryotic nature of the organism would confirm its placement in Protista.
Question 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?
Solution:
According to the five-kingdom classification, an organism can be placed in kingdom Fungi if it is eukaryotic, unicellular, and heterotrophic with a cell wall made of chitin. The mode of nutrition must be saprophytic or parasitic, obtaining nutrients by absorption from dead or living organic matter. Yeast is the only unicellular organism placed in Kingdom Fungi based on these characteristics.
Question 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. Instead of naming organisms directly, scientists recorded only structural, cellular and nutritional features as given in the table below.
The students realised that some organisms fit neatly into Whittaker’s five kingdom classification, while others challenged the very basis of this classification.
Based on the case study, answer the following questions
(i) Identify one organism that clearly belongs to the Kingdom Fungi. State one observation that supports your answer.
Solution:
Organism Q belongs to the Kingdom Fungi. It is multicellular with a cell wall, has no chlorophyll, and grows on dead organic matter, which is exactly how fungi like mushrooms work.
(ii) Which organism would be placed in the Kingdom Monera? Mention one characteristic that justifies this placement.
Solution:
Organism P belongs to Kingdom Monera. It is microscopic with no true nucleus (prokaryote) and has a rigid cell covering. These are the defining features of bacteria.
(iii) Organisms Rand Q are both eukaryotic, yet they are placed in different kingdoms. Analyse the criteria that separate them.
Solution:
Organism R belongs to Protista as it is unicellular, has flagella, and can do photosynthesis in light but is heterotrophic in darkness. Organism Q belongs to Fungi as it is multicellular, filamentous, has no chlorophyll, and absorbs food from dead matter. The key differences are level of organisation (unicellular vs multicellular), mode of nutrition, and body structure.
(iv) Explain why organism S cannot be classified using the mode of nutrition alone.
Solution:
Organism S is multicellular with a backbone and shows aquatic respiration during early life, which points to a vertebrate like an amphibian or fish. The mode of nutrition (heterotrophic) is shared by animals, fungi, and some protists. So nutrition alone is not enough. We need other features like presence of backbone, tissue organisation, and reproduction to correctly classify it under Vertebrata.
(v) Organism T does not fit into any of the five kingdoms. Which fundamental characteristic used in classification does it lack and what does this reveal about the limitations of classification systems?
Solution:
Organism T (a virus) lacks cellular organisation as it is a cellular and remains inactive outside a host cell. All five kingdoms are based on cellular life forms. This shows the biggest limitation of the five kingdom system, which is that it cannot classify non-cellular entities like viruses.
(vi) If classification were based only on habitat, which organisms might be incorrectly grouped together? Explain the scientific consequences of such a classification.
Solution:
Fish and whales would be grouped since both live in water, even though whales are mammals. Bats and birds would also be grouped together since both fly in air, even though bats are mammals and birds are a separate class. This would be scientifically wrong because their body organisation, reproduction, and evolutionary history are completely different. Habitat-based classification ignores fundamental biological differences and would give a very misleading picture of how organisms are actually related.
(vii) Imagine scientists discover a new organism that is multicellular, eukaryotic, lacks chlorophyll, and absorbs nutrients from a host externally. Should it be placed under fungi or animalia? Justify your reasoning using classification criteria.
Solution:
It should be placed under Kingdom Fungi because it absorbs nutrients externally from the host, which is a typical fungal feature, and it has no chlorophyll.
Animals ingest food internally and digest it inside their body. They do not absorb nutrients from the outside of a host. The external absorption of nutrients is the deciding factor that places this organism closer to Kingdom Fungi than Animalia.
Class 9 Science Chapter 12 Patterns in Life Diversity and Classification Question Answer (InText)
Think It Over
Question 1.
What do you understand by biodiversity?
Solution:
Biodiversity means the variety of living organisms found on Earth. It includes different types of plants, animals, and microorganisms, as well as the different habitats in which they live.
Question 2.
How does the grouping of organisms help us understand diversity?
Solution:
When we group organisms based on their similarities, it becomes easier to study them. We can understand how they are related to each other and how they evolved.
Question 3.
On what basis are plants and animals classified?
Solution:
They are classified based on things like their body structure, how they get food (autotrophic or heterotrophic), their cell type, how they reproduce, and their genetic similarity.
Question 4.
How does classification help address problems in farming?
Solution:
Classification helps farmers identify useful and harmful insects, choose the right crops, understand which plants resist drought or pests and maintain food security.
Pause and Ponder
Question 1.
If many organisms share common features, could they also share a common ancestry?
Solution:
Yes. When organisms share similar features like body structure or cell type, it usually means they evolved from the same ancestor long ago. The more features they share, more closely related they are.
Question 2.
How can a single-celled organism carry out all its life processes when billions of cells are required in multicellular organisms like us?
Solution:
A single-celled organism performs all life processes within one cell, making it self-sufficient. In multicellular organisms, different cells are specialised to perform different functions. No single cell can carry out all functions alone due to this division of labour. Therefore, billions of coordinated cells are needed to sustain life.
Question 3.
Which plant features reduce their dependence on water but still require moist conditions?
Solution:
Bryophytes have root-like rhizoids that help them absorb moisture from damp surfaces. They do not need to be in water, but they still need moisture around them, especially for reproduction.
Question 4.
Why do taller plants need specialised transport tissues?
Solution:
Taller plants cannot absorb water and food directly through their surface like small plants. They need xylem (to carry water upward) and phloem (to carry food) to transport nutrients to every part of the plant.
Question 5.
How do seeds and fruits affect where and how plants can survive?
Solution:
Seeds and fruits help plants spread to new places. Fruits protect seeds and help in their dispersal by wind, water, or animals. This allows plants to grow in different habitats, increasing their chances of survival and reducing competition with the parent plant.
Question 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?
Solution:
The beetle’s hard outer covering (exoskeleton) protects it from predators, stops water loss from its body, and supports strong muscles. This is why beetles can survive in dry, hot, and exposed places where earthworms cannot.
Question 7.
Does the term ‘biodiversity’ relate only to the variety of organisms, or does it encompass other elements?
Solution:
Biodiversity is more than just counting species. It also includes a variety of ecosystems like forests, oceans, and deserts, genetic diversity within species, and all the relationships between organisms and their environment.
Question 8.
If you find a new organism in a pond, what features will you observe to classify it and why?
Solution:
We would observe whether it is unicellular or multicellular, whether it has a nucleus, whether it moves, how it gets food and whether it has a cell wall. These features would help place it in the right kingdom.
Question 9.
Why do genetic studies provide deep information about living beings?
Solution:
Genetic studies provide information about the internal organisation and functioning of living beings at the molecular level. They reveal evolutionary relationships between organisms and explain the basis of inherited traits and diseases. Variations studied through genetics account for the diversity observed among living beings. Thus, genetic studies offer deep and precise insight into the biology of all living organisms.
Question 10.
How can changes in climate affect biodiversity?
Solution:
Climate change causes temperature rise, changed rainfall patterns, and habitat loss. Many species cannot adapt fast enough and may go extinct. When one species disappears, others that depend on it also suffer; it is like removing one piece from a puzzle.
Class 9 Science Chapter 2 Question Answer (Activities)
Activity: 1 Comparing and Classifying Organisms
Objective:
- To observe different organisms in an ecosystem.
- To classify organisms based on habitat, activity time, and features.
- To understand that organisms can be grouped using different criteria.
Materials Required:
- Given textbook picture (ecosystem image)
- Pencil/pen
- Observation notebook
Procedure:
- Carefully observe the given ecosystem image (day and night view).
- Identify as many organisms (animals/birds/insects) as possible.
- Note where each organism is seen: Air, Tree, Water, Ground/forest floor
- Observe when each organism appears active: Day, Night, Both
- Record your observations in the table.
- Try grouping organisms based on: Habitat, Activity time, Eating habits
Observation Table: Recording Observations
| Organism | Where seen (Air/Tree/Water/Ground) | Active (Day/Night/ Both) | Visible Feature(s) |
| Owl | Tree | Night | Feathers, big eyes |
| Tiger | Ground | Day | Stripes, sharp teeth |
| Monkey | Tree | Day | Tail, limbs |
| Rabbit | Ground | Day | Long ears |
| Deer | Ground | Day | Horns |
| Bat | Air/Tree | Night | Wings |
| Bird (Eagle) | Air | Day | Feathers, wings |
| Leopard | Tree/Ground | Night | Spots |
| Frog | Water/Ground | Both | Moist skin |
| Fish | Water | Day | Fins, scales |
Table: Grouping of Organisms
| Grouping Criterion | Organisms in Group | Feature Used |
| Carnivores | Tiger, Leopard, Eagle | Eating habits |
| Herbivores | Deer, Rabbit | Eating plants |
| Nocturnal | Owl, Bat, Leopard | Active at night |
| Diurnal | Monkey, Deer, Eagle | Active during day |
| Aquatic | Fish, Frog | Live in water |
| Arboreal | Monkey, Owl | Live on trees |
Conclusion:
- Organisms in an ecosystem show diversity in habitat, behaviour, and features.
- The same organism can belong to multiple groups depending on the criteria used.
- Classification helps in organising and understanding living organisms systematically.
Viva Voce Questions
Question 1.
What is meant by classification of organisms?
Question 2.
Why can the same organism be placed in different groups?
Question 3.
What are nocturnal animals? Give one example.
Question 4.
On what basis can organisms be grouped?
Question 5.
Why is classification important in biology?
Activity 2: Case Study – Pakke Tiger Reserve
Objective:
- To understand biodiversity and species distribution in a forest ecosystem.
- To learn how scientists classify and study organisms.
- To analyse the importance of habitat and interdependence among organisms.
Procedure:
- Carefully read the case study of Pakke Tiger Reserve.
- Identify key information such as: Number and types of species, Special organisms (e.g. hornbills), Habitat conditions (trees, fruits, forest regions)
- Observe how different species depend on: Tree size, Food availability
- Analyse how scientists study biodiversity using patterns.
- Answer the given case-based questions based on your understanding.
Case study:
Carefully read the given case study of Pakke Tiger Reserve.
The Pakke Tiger Reserve in Arunachal Pradesh is a forest where scientists have recorded nearly 300 bird species, which is striking given that India as a whole has about 1,300 bird species. Pakke is also known for supporting four species of hornbills — the Rufous-necked Hornbill, the Oriental Pied Hornbill, the Great Hornbill and the Wreathed Hornbill.
These large birds nest only in large, old trees with suitable cavities and feed on specific fruits.
As a result, different hornbill species are found in different parts of the forest depending on tree size and fruit availability.
Studying such patterns allows scientists to ask precise questions about biodiversity, such as
- How are species distributed within a forest? Which plants and animals are closely linked?
- How does classifying the four hornbill species help us understand biodiversity?
Think and discuss the case based on the following questions:
- How can scientists keep track of so many species?
- The four hornbills look similar in some ways. What features can help scientists distinguish them from one another?
- What would happen if the large, old trees disappeared from the forest?
Activity 3: Observing Bacteria and Cyanobacteria
Objective:
- To observe bacteria and cyanobacteria under a microscope.
- To understand that they are unicellular prokaryotes.
- To compare their basic structure and identify similarities.
Materials Required:
- Permanent slides of bacteria and cyanobacteria
- Microscope
- Notebook and pencil
Procedure:
- Take the prepared slides of bacteria and cyanobacteria.
- Place the slide on the microscope stage.
- Adjust the mirror/light and focus using the low-power objective.
- Observe the shape, size, and arrangement of the organisms.
- Repeat the observation using a higher magnification (if required).
- Compare both slides and note similarities and differences.
Observation Table:
| Feature | Bacteria | Cyanobacteria |
| Cell Type | Unicellular | Unicellular (sometimes colonial) |
| Cell Structure | Prokaryotic | Prokaryotic |
| Colour | Colourless | Green/blue-green |
| Mode of Nutrition | Heterotrophic/Autotrophic (photosynthetic) | Autotrophic |
| Habitat | Everywhere (soil, water, air) | Mostly aquatic |
Conclusion:
- Bacteria and cyanobacteria are unicellular prokaryotes grouped under Kingdom Monera.
- They lack a true nucleus and membrane-bound organelles.
- Cyanobacteria are photosynthetic, while bacteria show diverse modes of nutrition.
- Both play important roles in ecosystem functioning and nutrient cycling.
Viva Voce Questions
Question 1.
What are prokaryotic cells?
Question 2.
Why are bacteria placed under Kingdom Monera?
Question 3.
What is the main difference between bacteria and cyanobacteria?
Question 4.
Why are cyanobacteria called photosynthetic organisms?
Question 5. Name one useful and one harmful role of bacteria.
Activity 4: Preparation and Observation of Hay Infusion
Objective:
- To prepare a hay infusion and observe microorganisms.
- To study unicellular eukaryotes (Protista) under a microscope.
- To identify the presence of microscopic life in water.
Materials Required:
- Grass/straw/fodder
- Glass bottle
- Stagnant water/pond water
- Muslin cloth and thread
- Dropper
- Glass slide and coverslip
- Microscope
- Lab coat, gloves, mask (for safety)
Procedure:
Part A: Preparation of Hay Infusion
1. Collect a small sample of grass, straw, or fodder.
2. Take a glass bottle and fill one-fourth of it with the collected material.
3. Add stagnant or pond water to the bottle and mix well.
4. Cover the bottle with a muslin cloth and tie it with a thread.
5. Keep the bottle undisturbed for one week.
Part B: Observation Under Microscope
6. After a week, slightly open the bottle and take a drop of water using a dropper.
7. Place the drop on a clean glass slide and cover it with a coverslip.
8. Observe the slide under a microscope.
9. Look for moving microorganisms and compare them with known protists (e.g., Amoeba).
Precautions:
- Wear a lab coat, gloves, and a mask.
- The hay infusion may smell bad—handle carefully.
- Dispose of the solution properly after use.
Conclusion:
- Hay infusion contains microscopic organisms (protists).
- These organisms are unicellular eukaryotes found in water or moist places.
- Protists play an important role in Food chains, Oxygen production, and nutrient cycling
Viva Voce Questions
Question 1.
What is a hay infusion?
Question 2.
Why is stagnant water used in this activity?
Question 3.
Which type of organisms are observed in hay infusion?
Question 4.
Why are protists called unicellular eukaryotes?
Question 5.
Name one example of a protist observed under a microscope.
ACTIVITY 5: Study of Plant Groups (Kingdom-Plantae)
Objective:
- To study different plant groups based on their features.
- To analyse their adaptations for survival.
- To understand the advantages and challenges faced by each group.
Procedure:
- Carefully study the features of each plant group given in the table: Thallophyta, Bryophyta, Pteridophyta, Gymnosperms, Angiosperms
- Identify key characteristics such as: Body structure, Presence of vascular tissues, Mode of reproduction
- Analyse how these features help plants survive in their environment.
- Note down: Advantages for survival, Exceptions or challenges faced
- Record your observations in a tabular form.
Observation Table: Classes of Kingdom-Plantae
| Plant Group | Salient Features | Advantages for Survival | Exceptions / Challenges |
| Thallophyta | Simple thallus body, no differentiation | Easy absorption, survival in water | Cannot live on land |
| Bryophyta | No vascular tissue, need water for reproduction | Adapted to moist land | Always require moisture |
| Pteridophyta | True roots, stems, leaves; vascular tissues present | Better transport system, live on land | Reproduction depends on water |
| Gymnosperms | Needle – like leaves, seeds in cones | Adapted to dry conditions, no water needed for reproduction | Seeds not enclosed in fruits |
| Angiosperms | Flowers, fruits, well- developed tissues | Efficient reproduction, seed protection | Depend on pollination agents |
Conclusion:
- Plants show a gradual evolution from simple to complex forms.
- Advanced groups have better adaptations like: Vascular tissues, Seeds, Flowers
- These adaptations help plants survive in diverse environments, though each group still faces certain challenges.
Viva Voce Questions
Question 1.
What is the main difference between Thallophyta and Bryophyta?
Question 2.
Why are bryophytes called amphibians of the plant kingdom?
Question 3.
What advantage do vascular tissues provide to plants?
Question 4.
How are gymnosperms different from angiosperms?
Question 5.
Why are angiosperms considered the most advanced plants?