AHL Content Statements

• D4.3.9

  Phenology as research into the timing of biological events
  

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  Students should be aware that photoperiod and temperature patterns are examples of variables that influence the timing of biological events such as flowering, budburst and bud set in deciduous trees, bird migration and nesting.
  

• D4.3.10

  Disruption to the synchrony of phenological events by climate change
  

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  Students should recognize that within an ecosystem temperature may act as the cue in one population and photoperiod may be the cue in another. Include spring growth of the Arctic mouse-ear chickweed (Cerastium arcticum) and arrival of migrating reindeer (Rangifer tarandus) as one example. Also include a suitable local example or use the breeding of the great tit (Parus major) and peak biomass of caterpillars in north European forests as another.
  

• D4.3.11

  Increases to the number of insect life cycles within a year due to climate change
  

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  Use the spruce bark beetle (Ips typographus or Dendroctonus micans) as an example.
  

• D4.3.12

  Evolution as a consequence of climate change
  

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  Include changes in the fitness of colour variants of the tawny owl (Strix aluco) as a consequence of changes in snow cover.