BIO topic 9

• food chain

  1. producer gains energy from the sun(moss, grass)
  2. Primary consumer gains energy from producers (mountain hare)
  3. Secondary consumer gains energy from primary consumers (buzzard)
• pyramid of biomass - how it works

  as you go up the trophic level on the POB the size decreases bc the amount of energy decreases bc its lost

  producer has a large biomass, consumer has a small biomass
• what affect does reforestation have on biodiversity 


  ↑ biodiversity

  reforestation on deforested land, ↑ in n.o of trees bc gives food + shelter to organisms

  carefully planned reforestation → higher biodiversity
• humans interactions on ecosystem causing maintain in biodiversity - conservation schemes

  • protection of a species natural habitat
  • protection of a species in safe areas outside of their natural habitat + captive breeding programmes
• benefits of maintaing global and local biodiversity

  • job opportunities - conservation of animal species
  • ecotourism - impact of reforestation
  • ↓ damage to food chains
• biological factors affecting food security

  • ↑ human population
  • ↑ animal farming + eating fish + meat
  • environmental changes caused by humans
  • impacts of pests + pathogens
  • sustainability issues
• biological factors affecting food security - rising human population 


  ↑ pop need for ↑ food production for everyone to have food security
• biological factors affecting food security - ↑ animal farming + eating ↑ meat + fish 


  ↑ wealth amongst ppl so meatier diet, ↓ food security

  less food produced from animal farming then crop farming on the same area of land

  ↓biomass+ energy as u go up the food chain.so less meat + fish for everyone + risk of overfishing so none left in the future
• biological factors affecting food security - environmental challenges bc of humans


  ↑ use fossil fuels, ↑ greenhouse gases produced (CO2), ↑ global warming (type of climate change )→ affects rainfall patterns ect

  affects land crops r grown on, affects crop yeild
• biological factors affecting food security - pests + pathogens 


  affects crop yield so ↓sold as food

  when its a new pest ect crop yeild rlly ↓ bc crops may not be resistant to it.
• biological factors affecting food security - sustainability 


  biofuels (renewable alternative to fossil fuels) but take up land that could be used for food crops - need to have a sustainable balance
• how materials r constantly recycled thru the abiotic + bio components of an ecosystem

  1. biotic organisms take in elements thru the environment
  2. they turn them into complex compounds making up the biotic organisms
  3. elements are passed thru the food chain+then they are recycled(dead organisms broken down by decomposers)+used again in the food chain
• elements biotic organisms take from the environment

  • air - CO2,O2
  • soil - N2
• complex compounds biotic things are made up of


  carbohysrdates, proteins,fats