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Biology HL

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Chapter 12: Ecological Relationships

Trace nutrition, energy, matter and population change through ecosystems, then evaluate succession, biodiversity loss, conservation and climate-driven disruption.

Estimated chapter time: 1080 minutes

IB syllabus: A4.2 · C4.1 · C4.2 · D4.2 · D4.3 · SL and HL

Chapter Topics

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  1. 1How this chapter works
    1. 1.1Ecology across scales
    2. 1.2Models and evidence
    3. 1.3Chapter route
  2. 2Modes of nutrition
    1. 2.1Carbon, energy and oxygen
    2. 2.2Heterotrophic feeding groups
    3. 2.3Trophic levels and food webs
    4. 2.4Symbiosis and adaptations
  3. 3Transfer of energy and matter
    1. 3.1Energy flow and productivity
    2. 3.2Transfer efficiency and pyramids
    3. 3.3Nutrient cycling
    4. 3.4Carbon stores and fluxes
  4. 4Populations and interactions
    1. 4.1Interaction signs
    2. 4.2Quadrats and transects
    3. 4.3Capture–recapture
    4. 4.4Population growth
    5. 4.5Competition and allelopathy
    6. 4.6Predation and defence
    7. 4.7Cooperation and keystones
  5. 5Stability and succession
    1. 5.1Resistance and resilience
    2. 5.2Mesocosms and sustainability
    3. 5.3Agriculture and cycles
    4. 5.4Primary and secondary succession
    5. 5.5Climax and cycles
  6. 6The biodiversity crisis
    1. 6.1Dimensions of biodiversity
    2. 6.2Drivers of loss
    3. 6.3Conservation strategies
    4. 6.4Eutrophication
    5. 6.5Bioaccumulation and biomagnification
  7. 7Climate change and ecosystems
    1. 7.1Greenhouse forcing
    2. 7.2Feedback and tipping
    3. 7.3Range and ocean change
    4. 7.4Coral bleaching
    5. 7.5Phenology and evolution
    6. 7.6Restoration and response
  8. 8Chapter synthesis
    1. 8.1Causal chains
    2. 8.2High-value distinctions
    3. 8.3Data-question strategy

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