Ecosystems

1
Ecosystems

• Chapter 54 Ecosystems

2
Relationships, I

• Trophic structure / levels feeding relationships
  in an ecosystem
• Primary producers the trophic level that
  supports all others autotrophs
• Primary consumers herbivores
• Secondary and tertiary consumers carnivores
• Detrivores/detritus special consumers that
  derive nutrition from non-living organic matter
• Food chain trophic level food pathway

3
Relationships, II

• Food webs interconnected feeding relationship in
  an ecosystem

4
Energy Flow, I

• Primary productivity (amount of light energy
  converted to chemical energy by
  autotrophs) Gross (GPP) total energy
  
  Net (NPP) represents
  the storage of energy available to consumers
  Rs respiration
• NPP GPP - Rs
• Biomass primary productivity reflected as dry
  weight of organic material
• Secondary productivity the rate at which an
  ecosystem's consumers convert chemical energy of
  the food they eat into their own new biomass

5
Energy Flow, II

• Ecological efficiency of E transferred from
  one trophic level to the next (5-20) usually
  close to 10
• Pyramid of productivity multiplicative loss of
  energy in trophic levels
• Pyramid of numbers trophic representation of the
  number of organisms in an ecosystem

6
Chemical Cycling

• Biogeochemical cycles the various nutrient
  circuits, which involve both abiotic and biotic
  components of an ecosystem
• Water
• Carbon
• Nitrogen
• Phosphorus

7
Human Impact

• Biological magnification trophic process in
  which retained substances become more
  concentrated at higher levels
• Greenhouse effect warming of planet due to
  atmospheric accumulation of carbon dioxide
• Ozone depletion effect of chlorofluorocarbons
  (CFCs) released into the atmosphere
• Rainforest destruction
• Cause Overpopulation?