2.2 – Communities and Ecosystems

Food chains, food webs and ecological pyramids are models to show feeding relationships in ecosystems. Interactions between organisms and their environment results in transfers and transformations of energy and matter.


1Respiration and photosynthesis
2Food chains, food webs and feeding relationships
3Ecological pyramids
4Productivity pyramids and limitations to food chain length
5Bioaccumulation and biomagnification
Chapter Workbook
Vocabulary Sheet

  • Construct/modify a feeding relationship model using given data e.g. Using the Lotka-Volterra equations (information and model here).

Full PSOW here.

Essay Task

“DDT can accumulate through the food chain in increasing concentrations as a consequence of biomagnification. Compare the attitudes that an ecocentrist and an anthropocentrist may have on the use of DDT.” [9 marks]

View essay markbands

The essay should marked using the Paper 2, Section B essay markbands.

PDF Version

Google Docs Version

Google Docs 2.2 essay

Open the link and make a copy to your own drive. The doc can easily be shared as an “Assignment” on Google Classroom.

A markbands rubric designed for Google Classroom is available here.