Grade 9 · Science · Unit 2 of 11
Ecosystems in Balance
Cycles, food webs and succession
What your child practises
How the biosphere, hydrosphere, lithosphere and atmosphere interact, food webs and the 10% energy rule, the carbon, nitrogen, water and phosphorus cycles, succession and biodiversity, how people change ecosystems, and farming practices that protect soil and water.
Ontario Curriculum expectation: B2.1, B2.2, B2.4, B2.5, B2.7 · Earth's spheres, matter cycles and energy flow, biodiversity and succession, human effects on ecosystems, sustainable agriculture
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
Why does a higher biodiversity usually make an ecosystem more resilient?
- It removes the need for producers
- It means fewer species depend on each other
- If one species declines, others can fill its role
- It stops all change
Show answer
If one species declines, others can fill its role
Hint: Many species means more than one species doing each job.
Question 2
Which statement about matter and energy in an ecosystem is correct?
- Both are used up completely
- Matter is recycled, while energy flows through and leaves as heat
- Energy is recycled, while matter flows through
- Both cycle forever with no loss
Show answer
Matter is recycled, while energy flows through and leaves as heat
Hint: Atoms such as carbon are reused. Energy from the Sun is transformed and eventually lost as heat.
Question 3
Which sphere includes rock, soil and landforms?
- biosphere
- atmosphere
- lithosphere
- hydrosphere
Show answer
lithosphere
Hint: Litho means stone.
Question 4
Producer, consumer or decomposer? Sort each organism.
Sort into: 🌱 Producer · 🦌 Consumer · 🍄 Decomposer
- 🍁sugar maple
- 🌾cattails
- 🦆loon
- 🦌white-tailed deer
- 🐛earthworms in compost
- 🦠soil bacteria
Show answer
🌱 Producer: sugar maple, cattails · 🦌 Consumer: loon, white-tailed deer · 🍄 Decomposer: earthworms in compost, soil bacteria
Hint: Producers make their own food. Consumers eat other organisms. Decomposers break down dead matter.
Question 5
What does a producer do in an ecosystem?
- Eats other animals
- Breaks down dead matter
- Only lives in water
- Makes its own food, usually by photosynthesis
Show answer
Makes its own food, usually by photosynthesis
Hint: Plants and algae are the producers at the base of food chains.
Question 6
Which sphere of Earth includes all living things?
- biosphere
- atmosphere
- hydrosphere
- lithosphere
Show answer
biosphere
Hint: Bio means life.