Science> Year 8> Unit 1> Checkpoint 5

Checkpoint 5

This checkpoint tests Block E of the unit: ecosystems, food webs, energy and matter cycling, introduced species, population changes, endangered species and Australian biodiversity.

Lessons 21-25 10 MC 3 Short Answer Checkpoint 5 of 5 SC4-LIV-01 · Ecosystems & Biodiversity
CP5

Coverage

This checkpoint covers ecosystem interactions, energy flow, matter cycling, human impacts and biodiversity. Strong answers explain how parts of an ecosystem connect and why changes in one part can affect the whole system.

Lessons 21-22

Ecosystem components, producers, consumers, decomposers and food-web interactions.

Lesson 23

Energy pyramids, energy flow through trophic levels and matter cycling in ecosystems.

Lesson 24

Introduced species, population changes and how invasive species disrupt ecosystems.

Lesson 25

Endangered species, Australian biodiversity, extinction threats and conservation actions.

Checkpoint Standard
Weak answers list isolated facts. Strong answers use the structure of ecosystems to explain energy flow, matter cycling and the impact of human activity on biodiversity.
Real-World Anchor
Local creek survey: A class surveys a local creek and finds fewer native fish where willows have been introduced. The willows shade the water, change the temperature, and alter habitat. This shows how one introduced species can disrupt a whole ecosystem.
Real-World Anchor
Bushfire recovery: After a bushfire, areas with high biodiversity recover faster because different species play different roles in regrowth. Some plants resprout, some seeds germinate, and decomposers recycle nutrients. Biodiversity makes the ecosystem resilient.
MC Score
0 / 10
Short Answers
3
Self-Marked
0 / 3

Misconceptions to Fix

Wrong: Energy is recycled in an ecosystem

Right: Energy flows one way through trophic levels and most is lost as heat; matter is what cycles through ecosystems.

Wrong: Introduced species always help ecosystems

Right: Introduced species often lack natural predators and can outcompete or harm native species, disrupting the whole ecosystem.

Wrong: Endangered means extinct

Right: Endangered means at serious risk of extinction; the species still exists but needs protection to survive.

Wrong: Biodiversity just means having many animals

Right: Biodiversity includes the variety of all living things and their interactions, and it helps ecosystems resist and recover from disturbances.

Multiple Choice

UnderstandCore

1. What is the main role of producers in an ecosystem?

AThey make their own food using sunlight
BThey only eat other organisms
CThey break down dead matter
DThey have no role
UnderstandCore

2. In a food web, what happens to available energy at each trophic level?

AIt increases
BIt stays the same
CMost is lost as heat
DIt doubles
ApplyCore

3. Why do energy pyramids usually have a broad base and narrow top?

AThere are many producers and less energy reaches top predators
BPredators are always bigger
CProducers eat predators
DEnergy is created at the top
UnderstandCore

4. Which of these is part of the water cycle in an ecosystem?

APhotosynthesis only
BEvaporation and precipitation
CDigestion
DHibernation
ApplyCore

5. An introduced species such as the cane toad can harm an ecosystem because:

AIt is too small to matter
BIt has no natural predators and can outcompete natives
CIt only eats plants
DIt helps all native species
ApplyChallenge

6. A fox population increases in an area with many small native mammals. What is the most likely effect?

AThe native mammals increase
BThe native mammals may decline due to predation
CThe foxes become extinct
DNothing changes
UnderstandCore

7. Which term describes a species that is at serious risk of extinction?

AExtinct
BEndangered
CCommon
DIntroduced
AnalyseChallenge

8. Why is high biodiversity important for an ecosystem?

AIt makes the ecosystem look pretty
BIt helps the ecosystem resist and recover from disturbances
CIt means there are no predators
DIt reduces the number of food chains
ApplyChallenge

9. Which action is most likely to help conserve a threatened native species?

AClearing its habitat for housing
BProtecting its habitat and controlling introduced predators
CMoving it to a zoo and leaving the habitat
DIntroducing more competing species
AnalyseChallenge

10. Which statement best summarises Block E?

AEcosystems are simple collections of animals
BEnergy flows one way, matter cycles, and human actions can threaten biodiversity
COnly plants matter in ecosystems
DFood webs have no connection to real life

Energy Pyramid Diagram

Visual showing energy flow through producer, primary consumer, secondary consumer and top predator levels with heat loss at each step.

Australian Ecosystem Threats

Map or infographic showing introduced species locations and endangered species habitats in Australia.

Short Answer

Understand4 marks

Explain the difference between a food chain and a food web, and give one reason why a food web is a better model for most ecosystems. 1 mark for defining food chain. 1 mark for defining food web. 1 mark for stating food web shows more connections. 1 mark for explaining why this is more realistic.

Apply4 marks

Describe how an introduced species can change a native population. Use a real Australian example in your answer. 1 mark for naming an introduced species. 1 mark for explaining how it affects natives. 1 mark for using a real Australian example. 1 mark for explaining the ecosystem impact.

Analyse5 marks

Use the ideas of energy flow, matter cycling and biodiversity to explain why protecting Australian ecosystems matters for both wildlife and people. 1 mark for explaining energy flow. 1 mark for explaining matter cycling. 1 mark for explaining biodiversity importance. 1 mark for linking to wildlife. 1 mark for linking to human benefits.

Model Answers

+

Multiple Choice

1: A. Producers make their own food using sunlight through photosynthesis.

2: C. Most energy is lost as heat at each trophic level, which is why pyramids narrow.

3: A. There are many producers and less energy reaches top predators.

4: B. Evaporation and precipitation are key parts of the water cycle.

5: B. Introduced species such as cane toads often lack natural predators and outcompete natives.

6: B. Increased fox predation is likely to reduce small native mammal numbers.

7: B. Endangered means at serious risk of extinction.

8: B. High biodiversity helps ecosystems resist and recover from disturbances.

9: B. Habitat protection and predator control are the most effective conservation actions.

10: B. This statement captures energy flow, matter cycling and human impacts on biodiversity.

Short Answer 1 (4 marks)

A food chain shows one simple path of energy from producer to top consumer. A food web shows many interconnected food chains. A food web is a better model because most ecosystems have multiple feeding relationships, so a single chain is too simple.

1 mark for defining food chain. 1 mark for defining food web. 1 mark for stating food web shows more connections. 1 mark for explaining why this is more realistic.

Short Answer 2 (4 marks)

Introduced species can outcompete natives for food or shelter, or prey on them directly. For example, cane toads in northern Australia poison predators such as quolls and goannas that try to eat them, causing population declines.

1 mark for naming an introduced species. 1 mark for explaining how it affects natives. 1 mark for using a real Australian example. 1 mark for explaining the ecosystem impact.

Short Answer 3 (5 marks)

Energy flows through food webs from producers to consumers, supporting all life. Matter cycles through ecosystems so nutrients are reused. Biodiversity makes ecosystems stable and able to recover from change. Protecting Australian ecosystems matters because wildlife depends on these processes, and people benefit from clean water, pollination and healthy landscapes.

1 mark for explaining energy flow. 1 mark for explaining matter cycling. 1 mark for explaining biodiversity importance. 1 mark for linking to wildlife. 1 mark for linking to human benefits.

Checkpoint Summary

Ecosystems

Living and non-living components interact through food webs and nutrient cycles.

Energy & Matter

Energy flows one way through trophic levels; matter cycles through ecosystems.

Threats

Introduced species and habitat loss disrupt populations and reduce biodiversity.

Conservation

Protecting biodiversity keeps ecosystems stable and benefits wildlife and people.

Mark Checkpoint Complete
Save your progress once you have completed the multiple choice, attempted the short answers and self-marked your responses.
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