Chapter 12

• Food chain is feeding relationship of organisms.
• food web are inter-linked food chains
• structural adaptations are physical characteristics and features of an organism that help it to survive
• behavioural adaptions are the ways an organism behave to survive
• energy-efficient food chain is short
• Definitions

  1. population is a group of organisms of the same kind
  2. community is different populations living together in same habitat
  3. habitat is place where organism live and interact
  4. ecosystem is different communities interact with one anther and physical environment
  5. ecology is study of interactions between living and non-living things
• Environment

  ’Affect

  • waste food
  • waste electricty
  • waste water
  • excessive waste
• Environment

  ’Conserve

  • reduce use of fossil fuel
  • reduce consumption
  • introduce environmentally friendly practices
  • reforestation
• Physical factors

  • Any non-living parts of the physical environment, measured with data loggers and probes

  1. Light
  2. tempoerature
  3. Water
  4. Air
  5. Minerals
  6. pH
• Relationships

  Symbiosis - relationship between organisms

  Mutualism - both organisms benefit

  Predator-prey - kill and eat

  Parasitism - parasite benefit at expense/harm of host
• Stable ecosystem

  • interrelationships between organisms well maintained
  • affect by sudden disappearance/ decline of an organism
  • sudden change is environmental conditions
• Food chains

  • start with producer (any plant), trap light energy from sun to convert into stored chemical potential energy in food produced in photosynthesis, serve as sources of energy and food for consumer in food chain directly/indirectly
• Food chains

  • each stage is a trophic level
  • first trophic level is producer, second trophic level is primary consumer and third trophic level is secondary consumer
• Food web

  • inter-linked food chains
  • multiple organisms at each trophic level
• Energy and processes

  • respiration and photosynthesis -> flow of energy
  • respiration is release energy stored in food
  • photosynthesis makes energy from sun available to plants
  • only 10% of energy transferred at each trophic level
  • flow of energy is non-cyclical and one directional
• Energy loss

  1. Heat energy doing respiration
  2. Excretory waste
  3. Uneaten body parts
• Decomposers

  • break down remains of dead organisms and faeces return nutrients to environment and soil.
• Stable ecosystem

  • compost food waste, use as fertiliser, reduce amt of waste to burn, greenhouse gas reduced
  • alternate pckaging method like banana leaves
• Why flow of energy non-cyclical?

  Most energy lost as heat during respiration, not possible to reuse heat for growth or reproduction, one way flow
• Why flow of nutrients are cyclical?

  Transferred through feeding relationships, returned to environment when organisms die and are broken down by decomposers.