Ecosystems (Continuity and change)
- Natural selection
- Variation
- Mutation: new alleles
- Sexual reproduction: new combinations
- Overproduction and competition
- Carrying capacity
- Intraspecific competition
- Abiotic pressures
- Fitness and heritability
- Survive and reproduce
- Acquired traits not inherited
- Paradigm shift from Lamarckism
- Sexual selection
- Birds of paradise
- Endler's guppies
- Gene pools HL only
- Allele frequency
- Isolated populations
- Neo-Darwinism
- Types of selection HL only
- Directional
- Stabilizing
- Disruptive
- Artificial selection
- Hardy–Weinberg HL only
- p + q = 1
- p² + 2pq + q² = 1
- Five conditions
- Variation
- Stability and change
- Requirements for stability
- Energy supply
- Nutrient recycling
- Genetic diversity
- Climate within tolerance
- Amazon tipping point
- Transpiration makes rain
- Minimum area uncertain
- Percentage change
- Models and keystones
- Sealed mesocosms
- Sea otters
- Ochre starfish
- Sustainability
- Harvest below replacement
- Brazil nut, Atlantic cod
- Soil, leaching, inputs, carbon
- Pollution
- Eutrophication and BOD
- DDT and mercury
- Macro- and microplastics
- Rewilding
- Apex predators
- Habitat connectivity
- Hinewai Reserve
- Succession HL only
- Abiotic and biotic causes
- Primary: sand dunes
- Cyclical: heather
- Arrested succession HL only
- Climax community
- Livestock grazing
- Wetland drainage
- Requirements for stability
- Climate change
- Causes
- CO₂ from fossil fuels
- Methane from livestock
- Positive feedback
- Ice loss
- Permafrost thaw
- Deep ocean CO₂
- Fires and drought
- Tipping points
- Boreal forest browning
- Legacy carbon combustion
- Habitat change
- Emperor penguins, landfast ice
- Walruses, sea ice
- Reduced upwelling
- Coral bleaching, acidification
- Range shifts
- New Guinea birds upslope
- North American trees north
- Carbon sequestration
- Afforestation
- Forest regeneration
- Peatland restoration
- Phenology HL only
- Photoperiod vs temperature
- Chickweed and reindeer
- Great tits and caterpillars
- Life cycles and evolution HL only
- Spruce bark beetle
- Tawny owl colour
- Causes