Course review
Review each learning objective in this topic, then open its concept explanation or question set.
Learning objective
• Some ecosystems remain stable over long timescales despite local fluctuations • Ancient forests, deserts, and long-lived communities provide evidence of stability
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Stability requires energy input, nutrient cycling, biodiversity, and genetic diversity • Abiotic conditions must remain within tolerance ranges for key species
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Learning objective
• Amazon deforestation reduces transpiration, rainfall recycling, and regional cooling • Loss of forest can push rainforest toward savanna-like tipping points
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Learning objective
• Mesocosms model ecosystem stability under controlled experimental conditions • Closed bottle systems restrict matter exchange but allow light energy input
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Learning objective
• Keystone species have disproportionate effects on community structure • Removal can trigger trophic cascades and ecosystem instability
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Learning objective
• Sustainable harvesting removes biomass at or below replacement rate • Managed plant harvests and marine fish stocks require monitoring population recovery
Start with the concept explanation, then practise to create mastery evidence.
Learning objective
• Agricultural sustainability depends on soil conservation, nutrient balance, and biodiversity • Erosion, leaching, fertilizers, agrochemicals, irrigation, and carbon footprint are key factors
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Learning objective
• Eutrophication follows nitrate and phosphate enrichment of water • Algal blooms, decomposition, high biochemical oxygen demand, and hypoxia harm aquatic life
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Learning objective
• Biomagnification increases toxin concentration at higher trophic levels • DDT and mercury show how top predators receive the highest doses
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Learning objective
• Macroplastics and microplastics persist, fragment, and move through marine ecosystems • Effects include entanglement, ingestion, toxin transport, and food-web impacts
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Learning objective
• Rewilding restores natural processes, trophic interactions, and habitat connectivity • Keystone species reintroductions can restart trophic cascades and reduce intensive management
Start with the concept explanation, then practise to create mastery evidence.