Ecosystems, Food Chains and Biodiversity — O/L Science

What must I remember about Ecosystems, Food Chains and Biodiversity?

• Food web: multiple interconnected food chains; energy flows producer → consumer
• Trophic levels: producers (T1), primary consumers (T2), secondary (T3), tertiary (T4)
• Carbon cycle: photosynthesis (CO₂→ organic C); respiration/combustion (organic C → CO₂)
• Nitrogen cycle: fixation → nitrification → assimilation → denitrification
• Biodiversity: species richness + evenness; high diversity → more resilient ecosystem

Test yourself (1 minute)

1. Carbon cycle

   photosynthesis (fixes C), respiration/combustion (releases C)

2. Nitrogen cycle

   fixation (lightning, bacteria) → nitrification → uptake → denitrification

3. Biodiversity

   variety of species; high diversity = resilient ecosystem

Practise Ecosystems, Food Chains and Biodiversity questions today

Must know

• Only ~10% energy passes to each trophic level
• Threats: deforestation, pollution, overfishing, invasive species, climate change

Source: NIE O/L Science — Unit 7: Ecosystems

What should I study first?

Next in the syllabus

Where does Ecosystems, Food Chains and Biodiversity fit in the syllabus?

Grade 11 · Term 3