BRAINCAKE

Ecosystems and material cycles

Edexcel GCSE BiologyTopic 9 of 919 lessons

Revision notes for Ecosystems and material cycles in Edexcel Biology (1BI0). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.

  1. Levels of organisation in an ecosystemEcologists study living things at different levels of organisation.
  2. Abiotic and biotic factors affecting communitiesThe size and make-up of a community is affected by abiotic factors, which are non-living, and biotic factors, which are living.
  3. Interdependence in a communityNo species in a community lives completely alone.
  4. Parasitism and mutualismSome organisms can only survive because of a close relationship with another species.
  5. Core practical: fieldwork with quadrats and belt transectsThis core practical investigates how the distribution of organisms changes along an environmental gradient, for example from a shaded area under a…
  6. Estimating population size from quadrat dataIt is usually impossible to count every organism in a habitat, so ecologists sample it.
  7. Energy transfer and trophic levelsProducers capture only a small fraction of the light that reaches them and store it as chemical energy in their biomass, the mass of living material.
  8. Efficiency of energy transfer and percentage biomassThe efficiency of a transfer shows what percentage of the energy at one trophic level is passed on to the next.
  9. Human interactions: fish farming and non-indigenous speciesHumans affect ecosystems in positive and negative ways.
  10. Benefits of maintaining biodiversityBiodiversity is the variety of different living organisms in an ecosystem.
  11. Biological factors affecting food securityFood security means that a population has a reliable supply of enough safe and nutritious food.
  12. How materials cycle in an ecosystemThe Earth does not gain new matter, and the supply of elements such as carbon and nitrogen is limited.
  13. The carbon cycleThe carbon cycle moves carbon between the air, living things and the soil.
  14. The water cycle and potable waterThe water cycle moves water between the sea, the air, the land and living things.
  15. Nitrates and the nitrogen cyclePlants need nitrates from the soil to make amino acids, which are joined to make proteins for growth.
  16. Indicator species and pollutionAn indicator species is a living organism whose presence or absence tells us about the conditions in a habitat.
  17. Decomposition and food preservationFood goes off because bacteria and fungi feed on it.
  18. Decomposition and compostingComposting is decomposition that we want.
  19. Calculate rate changes in the decay of biological materialDecay is the breakdown of dead plant and animal material by microorganisms.

All Edexcel GCSE Biology topics