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Primary 6 PSLE Science Diversity Quiz

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Primary 6 PSLE Science Quiz - Diversity

Name: ___________________________
Class: Primary 6 _______
Date: _______________
Score: _______ / 50

Duration: 45 minutes
Total Marks: 50

Instructions:

Answer all questions.
For Section A, choose the correct option and write its letter (A, B, C, or D) in the brackets provided.
For Section B and C, write your answers in the spaces provided.
The number of marks for each question is shown in brackets [ ].
Read each question carefully before answering.

Section A: Multiple-Choice Questions (20 marks)

Questions 1 to 10 carry 2 marks each.

1. Which of the following groups of organisms are all classified as fungi? [2]

( ) A. Mushroom, yeast, mould
B. Fern, moss, algae
C. Bacteria, virus, amoeba
D. Coral, sponge, jellyfish

2. The diagram below shows a dichotomous key used to classify four animals W, X, Y and Z. [2]

<image_placeholder> id: Q2-fig1 type: diagram linked_question: Q2 description: Dichotomous key for classifying four animals W, X, Y, Z based on body covering and reproduction method labels: Start -> Has feathers? -> Yes -> Bird (W); No -> Has hair/fur? -> Yes -> Mammal (X); No -> Lays eggs in water? -> Yes -> Amphibian (Y); No -> Reptile (Z) values: Animal W: Bird; Animal X: Mammal; Animal Y: Amphibian; Animal Z: Reptile must_show: Clear branching with yes/no questions, four end points labelled W, X, Y, Z </image_placeholder>

Based on the key, which animal is most likely a frog? [2] ( ) A. W
B. X
C. Y
D. Z

3. Study the table below showing characteristics of four organisms. [2]

Organism	Makes its own food	Reproduces by spores	Has roots, stem and leaves
P	Yes	No	Yes
Q	No	Yes	No
R	Yes	Yes	No
S	No	No	Yes

Which organism is a non-flowering plant? [2] ( ) A. P
B. Q
C. R
D. S

4. The diagram below shows a food web in a garden community. [2]

<image_placeholder> id: Q4-fig1 type: diagram linked_question: Q4 description: Food web with grass, grasshopper, frog, snake, hawk, mouse, and decomposers labels: Grass (producer) -> Grasshopper, Mouse; Grasshopper -> Frog; Mouse -> Snake; Frog -> Snake, Hawk; Snake -> Hawk; All dead organisms -> Decomposers (bacteria, fungi) values: 7 organisms shown with arrows indicating energy flow must_show: Clear arrows from prey to predator, decomposers connected to all dead organisms, producer at base </image_placeholder>

How many food chains in the food web include the frog as a consumer? [2] ( ) A. 1
B. 2
C. 3
D. 4

5. Which of the following statements about microorganisms is correct? [2]

( ) A. All microorganisms are harmful to humans.
B. Bacteria are larger than fungi.
C. Yeast is a fungus used in bread-making.
D. Viruses can reproduce on their own outside a host cell.

6. The table below shows the characteristics of four vertebrates. [2]

Animal	Body covering	Breathing organ	Reproduction
A	Scales	Gills	Lays eggs in water
B	Feathers	Lungs	Lays eggs on land
C	Hair	Lungs	Gives birth to live young
D	Moist skin	Lungs and skin	Lays eggs in water

Which animal is a mammal? [2] ( ) A. A
B. B
C. C
D. D

7. A student observed an organism with the following characteristics: [2]

It is unicellular.
It has a cell wall but no chloroplasts.
It reproduces by binary fission.

Which group does this organism most likely belong to? [2] ( ) A. Bacteria
B. Fungi
C. Protists
D. Plants

8. The diagram below shows a pyramid of numbers for a food chain. [2]

<image_placeholder> id: Q8-fig1 type: diagram linked_question: Q8 description: Pyramid of numbers with four trophic levels labels: Level 1 (Producer): 1000 grass plants; Level 2 (Primary consumer): 100 grasshoppers; Level 3 (Secondary consumer): 10 frogs; Level 4 (Tertiary consumer): 1 hawk values: 1000, 100, 10, 1 must_show: Pyramid shape with bars representing number of organisms at each level, labels for each trophic level </image_placeholder>

Which of the following food chains does this pyramid represent? [2] ( ) A. Grass → Grasshopper → Frog → Hawk
B. Hawk → Frog → Grasshopper → Grass
C. Grass → Frog → Grasshopper → Hawk
D. Grasshopper → Grass → Frog → Hawk

9. Which of the following is not a characteristic of flowering plants? [2]

( ) A. They reproduce by seeds.
B. They produce flowers.
C. They reproduce by spores.
D. They have roots, stems and leaves.

10. The diagram below shows a cell observed under a microscope. [2]

<image_placeholder> id: Q10-fig1 type: diagram linked_question: Q10 description: Plant cell with visible cell wall, cell membrane, cytoplasm, nucleus, chloroplasts, and large central vacuole labels: Cell wall, Cell membrane, Cytoplasm, Nucleus, Chloroplasts, Large central vacuole values: N/A must_show: All listed organelles clearly labelled, rectangular shape indicating plant cell </image_placeholder>

Based on the cell structures visible, this cell is most likely from a: [2] ( ) A. Mushroom
B. Onion
C. Human cheek
D. Bacteria

Section B: Structured Questions (20 marks)

Questions 11 to 15 carry 4 marks each.

11. The diagram below shows five organisms. [4]

<image_placeholder> id: Q11-fig1 type: diagram linked_question: Q11 description: Five organisms: (a) Mushroom, (b) Fern, (c) Bacterial cell (rod-shaped), (d) Moss, (e) Yeast cells (budding) labels: A: Mushroom with cap and gills; B: Fern with fronds; C: Rod-shaped bacterial cell; D: Moss carpet; E: Yeast cells showing budding values: N/A must_show: Clear distinguishable features of each organism type </image_placeholder>

(a) Classify the five organisms into three groups based on how they obtain food. Write the letters (A, B, C, D, E) in the table below. [2]

Group	Organisms (letters)
Producers
Decomposers
Cannot be determined from diagram alone

(b) State one similarity between the mushroom (A) and yeast (E) in terms of how they obtain nutrients. [1]

12. Study the food web below. [4]

<image_placeholder> id: Q12-fig1 type: diagram linked_question: Q12 description: Food web: Phytoplankton -> Zooplankton, Small fish; Zooplankton -> Small fish, Jellyfish; Small fish -> Large fish, Seabird; Jellyfish -> Sea turtle; Large fish -> Shark; Seabird -> Shark; Sea turtle -> Shark; All -> Decomposers labels: Phytoplankton (producer), Zooplankton, Small fish, Jellyfish, Large fish, Seabird, Sea turtle, Shark (top predator), Decomposers values: 8 living organisms + decomposers must_show: Clear energy flow arrows, producer at base, multiple interconnected chains </image_placeholder>

(a) Write one food chain with four organisms from the food web. [1]

(b) If a disease kills all the zooplankton, explain what will happen to the small fish population in the short term. [2]

(c) The shark is the top predator. Explain why the number of sharks is usually much smaller than the number of phytoplankton. [1]

13. The table below shows the characteristics of four organisms P, Q, R and S. [4]

Characteristic	P	Q	R	S
Nucleus present	Yes	Yes	No	Yes
Cell wall present	Yes	No	Yes	Yes
Chloroplasts present	Yes	No	No	No
Mode of nutrition	Autotrophic	Heterotrophic	Heterotrophic	Heterotrophic (absorptive)

(a) Which organism (P, Q, R or S) is a plant? [1]

(b) Which organism (P, Q, R or S) is a bacterium? [1]

(d) State one difference between organism Q and organism S in how they obtain nutrients. [1]

14. A student set up an experiment to investigate the conditions needed for mould growth on bread. [4]

<image_placeholder> id: Q14-fig1 type: experimental_setup linked_question: Q14 description: Four petri dishes with bread slices: Dish 1 - Dry bread, 25°C, light; Dish 2 - Moist bread, 25°C, dark; Dish 3 - Moist bread, 5°C (fridge), dark; Dish 4 - Moist bread, 25°C, light labels: Dish 1: Dry, 25°C, Light; Dish 2: Moist, 25°C, Dark; Dish 3: Moist, 5°C, Dark; Dish 4: Moist, 25°C, Light values: Temperature: 25°C (room temp) vs 5°C (fridge); Moisture: Dry vs Moist; Light: Light vs Dark must_show: Four clearly labelled setups with conditions indicated </image_placeholder>

(a) Which two dishes should the student compare to find out if light affects mould growth? [1]

(b) In which dish (1, 2, 3 or 4) would mould grow best? Explain your answer. [2]

15. The diagram below shows a pyramid of biomass for a food chain in a lake. [4]

<image_placeholder> id: Q15-fig1 type: diagram linked_question: Q15 description: Pyramid of biomass with four trophic levels labels: Level 1: Phytoplankton (800 g/m²); Level 2: Zooplankton (80 g/m²); Level 3: Small fish (8 g/m²); Level 4: Large fish (0.8 g/m²) values: 800, 80, 8, 0.8 g/m² (each level 10% of previous) must_show: Pyramid shape with biomass values labelled, trophic levels named </image_placeholder>

(a) Calculate the percentage of biomass transferred from phytoplankton to zooplankton. [1]

(b) Explain why the biomass decreases at each trophic level. [2]

(c) If the phytoplankton population suddenly doubles, what would happen to the zooplankton population after some time? Explain. [1]

Section C: Open-Ended Questions (10 marks)

Questions 16 to 20 carry 2 marks each.

16. Classification Key Construction [2]

A student found four unknown organisms in a garden. She recorded their characteristics:

Organism W: Green, has roots and leaves, reproduces by seeds
Organism X: Green, no roots/stems/leaves, reproduces by spores, grows in damp places
Organism Y: White, thread-like, grows on dead wood, reproduces by spores
Organism Z: Has wings, three body parts, six legs

Construct a dichotomous key (using 1a/1b, 2a/2b format) to identify these four organisms. Use observable characteristics only.

17. Adaptations for Survival [2]

The diagram below shows a cactus and a water lily. [2]

<image_placeholder> id: Q17-fig1 type: diagram linked_question: Q17 description: Side-by-side comparison: Cactus (thick stem, spines, shallow widespread roots) and Water lily (broad floating leaves, long flexible stem, roots in mud) labels: Cactus: Thick fleshy stem, Spines instead of leaves, Shallow widespread roots; Water lily: Broad flat floating leaves, Long flexible stem, Roots anchored in mud values: N/A must_show: Clear structural adaptations labelled for both plants </image_placeholder>

(a) State one structural adaptation of the cactus that helps it survive in the desert. Explain how it helps. [1]

(b) State one structural adaptation of the water lily that helps it survive in a pond. Explain how it helps. [1]

18. Energy Flow and Decomposers [2]

In a forest ecosystem, fallen leaves accumulate on the forest floor. Over time, they disappear and nutrients return to the soil.

(a) Name the group of organisms mainly responsible for breaking down the fallen leaves. [1]

(b) Explain why these organisms are essential for the ecosystem. [1]

19. Cell Diversity [2]

The diagrams below show two different cells, Cell M and Cell N. [2]

<image_placeholder> id: Q19-fig1 type: diagram linked_question: Q19 description: Two cells side by side: Cell M (plant cell) - rectangular, cell wall, large vacuole, chloroplasts; Cell N (animal cell) - irregular shape, no cell wall, small vacuoles, no chloroplasts labels: Cell M: Cell wall, Cell membrane, Cytoplasm, Nucleus, Chloroplasts, Large central vacuole; Cell N: Cell membrane, Cytoplasm, Nucleus, Small vacuoles, Mitochondria values: N/A must_show: Clear differences in shape, presence/absence of cell wall, chloroplasts, vacuole size </image_placeholder>

(a) Identify one structure present in Cell M but absent in Cell N. [1]

(b) State the function of the structure you identified in (a). [1]

20. Man's Impact on Biodiversity [2]

A developer plans to clear a 5-hectare forest to build a shopping mall. An environmental group proposes keeping 2 hectares as a nature reserve.

(a) State one negative impact on biodiversity if the entire forest is cleared. [1]

(b) Explain how keeping part of the forest as a nature reserve helps reduce this impact. [1]

End of Quiz

Answers

Primary 6 PSLE Science Quiz - Diversity (Answer Key)

Total Marks: 50

Section A: Multiple-Choice Questions (20 marks)

1. Answer: A [2]

Explanation: Mushroom, yeast, and mould are all fungi. Ferns and mosses are non-flowering plants. Bacteria and viruses are microorganisms but not fungi. Corals, sponges, and jellyfish are animals.

2. Answer: C [2]

Explanation: Following the dichotomous key: Frogs are amphibians. They do not have feathers or hair/fur, and they lay eggs in water. This leads to Animal Y.

3. Answer: B [2]

Explanation: Non-flowering plants (like ferns and mosses) make their own food (photosynthesis), reproduce by spores, and do not have true roots, stems, and leaves (mosses have simple structures). Organism Q matches this. P is a flowering plant. R could be algae. S is an animal.

4. Answer: B [2]

Explanation: Food chains including frog as consumer:

Grass → Grasshopper → Frog → Snake → Hawk
Grass → Grasshopper → Frog → Hawk (Note: Frog is eaten by both snake and hawk, creating two chains where frog is a consumer.)

5. Answer: C [2]

Explanation: Yeast is a single-celled fungus used in bread-making (fermentation produces CO₂). A is false - many microorganisms are beneficial. B is false - bacteria are generally smaller than fungi. D is false - viruses need a host cell to reproduce.

6. Answer: C [2]

Explanation: Mammals have hair/fur, breathe with lungs, and give birth to live young (mostly). Animal C matches all three characteristics.

7. Answer: A [2]

Explanation: Bacteria are unicellular, have cell walls (made of peptidoglycan), lack chloroplasts, and reproduce by binary fission. Fungi have cell walls made of chitin. Protists are diverse but typically have nucleus. Plants have chloroplasts.

8. Answer: A [2]

Explanation: Pyramid of numbers shows producers at the base (largest number) and top predator at the apex (smallest number). Grass (1000) → Grasshopper (100) → Frog (10) → Hawk (1) matches the pyramid.

9. Answer: C [2]

Explanation: Flowering plants reproduce by seeds, not spores. Non-flowering plants (ferns, mosses) reproduce by spores.

10. Answer: B [2]

Explanation: The cell has a cell wall, chloroplasts, and a large central vacuole - characteristic of a plant cell. Onion cells are classic plant cells. Mushroom is fungus (no chloroplasts). Human cheek is animal cell (no cell wall, no chloroplasts). Bacteria has no nucleus or membrane-bound organelles.

Section B: Structured Questions (20 marks)

11. [4]

(a) [2]

Group	Organisms (letters)
Producers	B, D
Decomposers	A, C, E
Cannot be determined from diagram alone	(none)

Marking: 1 mark for correct producers (B, D - fern and moss are plants), 1 mark for correct decomposers (A, C, E - mushroom, bacteria, yeast are decomposers).

(b) [1] Both obtain nutrients by external digestion and absorption (secrete enzymes onto food, break it down externally, then absorb the nutrients).

(c) [1] Ferns and mosses are plants because they have chlorophyll and make their own food through photosynthesis. They are non-flowering plants because they reproduce by spores, not seeds.

12. [4]

(a) [1] Phytoplankton → Zooplankton → Small fish → Large fish → Shark
(Other valid 4-organism chains: Phytoplankton → Zooplankton → Small fish → Seabird → Shark; Phytoplankton → Zooplankton → Jellyfish → Sea turtle → Shark)

(b) [2]

Small fish population will decrease [1].
Zooplankton is a food source for small fish. With no zooplankton, small fish lose one food source, leading to less food available, increased competition, and population decline [1].

(c) [1] Energy is lost at each trophic level (as heat, waste, uneaten parts). Only about 10% of energy/biomass is transferred. Thus, the biomass/population at higher trophic levels must be much smaller to be supported by the base.

13. [4]

(a) [1] P (Has nucleus, cell wall, chloroplasts, autotrophic - plant characteristics)

(b) [1] R (No nucleus, has cell wall, no chloroplasts, heterotrophic - bacterium characteristics)

(c) [1] S (Has nucleus, cell wall, no chloroplasts, absorptive heterotrophic nutrition - fungus characteristics)

(d) [1] Organism Q (animal) ingests food and digests it internally.
Organism S (fungus) secretes enzymes onto food for external digestion and absorbs the nutrients.

14. [4]

(a) [1] Dish 2 and Dish 4 (Both have moist bread at 25°C in dark vs light - only light differs)

(b) [1] Dish 2 [1]
Explanation: Mould grows best in moist, warm (room temperature), and dark conditions. Dish 2 has all three. Dish 1 is dry. Dish 3 is too cold (5°C slows growth). Dish 4 has light which can inhibit some moulds.

(c) [1] Type of bread / size of bread slice / type of petri dish / species of mould spores introduced (any one controlled variable)

15. [4]

(a) [1] (80 g/m² ÷ 800 g/m²) × 100% = 10%

(b) [2]

Energy/biomass is lost at each trophic level through: respiration (heat), waste (faeces/urine), and uneaten parts (bones, fur) [1].
Only a small fraction (typically ~10%) is converted into new biomass of the consumer [1].

(c) [1] Zooplankton population would increase because there is more food (phytoplankton) available, allowing more zooplankton to survive and reproduce.

Section C: Open-Ended Questions (10 marks)

16. [2]

Dichotomous Key:

1a. Organism is a plant (green, makes own food) ........................................... Go to 2
1b. Organism is an animal ............................................................................. Z (insect - wings, three body parts, six legs)

2a. Plant has true roots, stems, leaves and reproduces by seeds ..................... W (flowering plant)
2b. Plant lacks true roots/stems/leaves, reproduces by spores ......................... Go to 3

3a. Plant has leaf-like and stem-like structures (fronds) ................................. X (fern)
3b. Plant is small, carpet-like, grows in damp places ..................................... Y (moss)

Marking: 1 mark for correct structure (1a/1b, 2a/2b, 3a/3b format with observable characteristics). 1 mark for all four organisms correctly identified at endpoints.

17. [2]

(a) [1] Adaptation: Thick, fleshy stem / Spines instead of leaves / Shallow widespread roots (any one)
Explanation:

Thick stem: Stores water for use during drought.
Spines: Reduce water loss through transpiration (smaller surface area) and protect from herbivores.
Shallow widespread roots: Quickly absorb rainwater over large area before it evaporates.

(b) [1] Adaptation: Broad flat floating leaves / Long flexible stem / Roots anchored in mud (any one)
Explanation:

Broad floating leaves: Maximise sunlight absorption for photosynthesis on water surface.
Long flexible stem: Allows leaves to float on surface regardless of water depth changes.
Roots in mud: Anchor plant and absorb nutrients from pond bottom.

18. [2]

(a) [1] Decomposers (bacteria and fungi)

(b) [1] They break down dead organic matter and waste, recycling nutrients (like nitrogen, phosphorus) back into the soil/environment for producers (plants) to reuse. Without them, nutrients would be locked in dead matter and the ecosystem would run out of essential nutrients.

19. [2]

(a) [1] Cell wall / Chloroplasts / Large central vacuole (any one)

(b) [1]

Cell wall: Provides structural support and maintains cell shape (prevents bursting).
Chloroplasts: Site of photosynthesis - traps light energy to make food (glucose).
Large central vacuole: Stores water, nutrients, waste; maintains turgor pressure for support.

20. [2]

(a) [1] Loss of habitat for plants and animals living in the forest, leading to decrease in biodiversity / extinction of some species / disruption of food webs.

(b) [1] The nature reserve preserves part of the original habitat, allowing some species to survive and maintain their populations. It acts as a refuge and can serve as a source for recolonisation of surrounding areas. It maintains ecological processes (pollination, seed dispersal, nutrient cycling) in that area.

End of Answer Key