Ecosystems and tropical rainforests
Rainforests look chaotic and are in fact tightly organised. Once you can explain nutrient cycling and adaptation, deforestation questions answer themselves.
Lesson overview
What you'll learn in this lesson
Describe ecosystems, tropical rainforests and hot deserts or cold environments, including sustainable management.
Key learning points
- • Structure and interdependence
- • Nutrient cycling and thin soils
- • Deforestation: causes and impacts
- • Sustainable management
This lesson at a glance
- 30 minutes
- 20 parts to scroll through
- 4 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 20
Visual introductionPicture this
Ecosystems and tropical rainforests
Rainforests look chaotic and are in fact tightly organised. Once you can explain nutrient cycling and adaptation, deforestation questions answer themselves.
In a nutshell
Describe ecosystems, tropical rainforests and hot deserts or cold environments, including sustainable management.
Learning cycle
Part 2 of 20
Learning cycle 1 of 2
Part 1 · Structure and interdependence
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 20
Learn
Structure and interdependence
Emergents, canopy, under-canopy, shrub layer and forest floor each receive different light, which drives the plants and animals found there. Climate, soil, water and living things are interdependent: remove the trees and rainfall, soil stability and nutrient supply all change together.
Reset break
Part 4 of 20
Pause
That's sitting 1 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Explore the idea
Part 5 of 20
Learn
Nutrient cycling and thin soils
Almost all nutrients are stored in the biomass, not the soil. Rapid decomposition in hot, humid conditions returns nutrients to the trees within weeks, and heavy rain leaches anything left. That is why cleared rainforest land loses fertility within a few harvests.
Quick check
Part 6 of 20
Quick check
Part 7 of 20
Reset break
Part 8 of 20
Pause
That's sitting 2 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Learning cycle
Part 9 of 20
Learning cycle 2 of 2
Part 2 · Deforestation: causes and impacts
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 10 of 20
Learn
Deforestation: causes and impacts
Commercial farming, cattle ranching, logging, mining, road building, hydroelectric schemes and population pressure all drive clearance. Impacts include biodiversity loss, soil erosion, reduced carbon storage, disrupted rainfall and displacement of indigenous communities, set against economic development, employment and export income.
Explore the idea
Part 11 of 20
Learn
Sustainable management
Selective logging and replanting, conservation and education, ecotourism, international debt-reduction agreements and hardwood agreements all reduce loss without ending economic use. Evaluate them by cost, enforceability and who benefits.
Reset break
Part 12 of 20
Pause
That's sitting 3 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 13 of 20
Quick check
Part 14 of 20
Explore the idea
Part 15 of 20
Worked example
Model answer: 'Explain why rainforest soils lose fertility quickly after clearance' (4 marks)
In an intact rainforest almost all nutrients are held in the biomass rather than the soil, and are recycled rapidly as leaf litter decomposes in hot, humid conditions and is taken up again by the trees. When the forest is cleared, the store of nutrients is removed with the trees, so little remains to replenish the soil. Without a canopy, heavy convectional rainfall reaches the ground directly and leaches the remaining soluble nutrients downwards, so crop yields fall within a few years and farmers move on.
Reset break
Part 16 of 20
Pause
That's sitting 4 of 5 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Challenge round
Part 17 of 20
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 18 of 20
Game · Recall cards
Where are most rainforest nutrients stored?
Card 1 of 4
Mastery quiz
Part 19 of 20
Marked quiz
End of lesson quiz: Ecosystems and tropical rainforests
4 questions, marked with the reasoning shown. No timer.
1. Where are most rainforest nutrients stored?
2. Why does leaching increase after clearance?
3. Which is a sustainable management strategy rather than a cause of loss?
4. Which impact of deforestation is global rather than local?
Lesson round-up
Part 20 of 20
Lesson round-up
Ready when you are
Quiz score
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Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?
Ask LunaPart 1 of 20 · Watch & discover