ECOSYSTEM ECOLOGY L26

Question 1

ecosystem

Answer 1

• all living organisms in an area and abiotic environment
• E flow is linear
• nutrients are cycled

Question 2

trophic levels

Answer 2

• groups of species based on main source of E/nutrition

Question 3

primary producers

Answer 3

• autotrophs
• photosynthetic
• build own biomass
• plants (land), algae and cyanobacteria (aquatic)

Question 4

consumers

Answer 4

• heterotrophs
• primary: herbivores
• secondary: carnivores that consume herbivores
• tertiary: carnivores that consume other carnivores

Question 5

detritivores

Answer 5

• E from dead organic mater

- break down, recycle organic materials back into environment

Question 6

primary production

Answer 6

• amount of light E converted to chemical E by autotrophs during a given time
• GPP
• (totally primary production in an ecosystem) - (amount of E converted to chemical E)

Question 7

NPP

Answer 7

• E that remains in tissues after cellular respiration
• (GPP) - (autotrophic respiration)
• 1/2GPP
• represents E available to next trophic level

Question 8

assimilation

Answer 8

• total E taken in
• used for growth, reproduction, respiration
• excludes E lost in feces

Question 9

net secondary production

Answer 9

• chemical E in consumers

- food converted to biomass and reproduction

Question 10

production efficiency

Answer 10

• how much E taken in incorporated as biomass

- 1-3% for birds and mammals and 10% for fish - always low

Question 11

trophic efficiency

Answer 11

• % of production transferred from one trophic level to the next
• E lost
• not all organic matter consumed
• usually about 10%
• 90% of available E (net secondary production) not transferred

Question 12

biogeochemical cycles

Answer 12

• movement of matter through biotic and abiotic components of ecosystems

Question 13

water cycle

Answer 13

• essential for all organisms
• evaporation: liquid – gas
• transpiration: movement from ground – air through plants
• condensation: water vapor – clouds
• precipitation: atmosphere – ground

Question 14

carbon cycle

Answer 14

• organic molecules
• absorbed via photosynthesis
• released via respiration, combustion, volcanism

Question 15

phosphorus cycle

Answer 15

• nucleic acids, phospholipids, ATP
• weathering/erosion adds phosphate to soil
• incorporated into biomass by producers
• released via excretion or decomposition

Question 16

nitrogen cycle

Answer 16

• amino acids, nucleic acids
  1. nitrogen fixation: abiotic – biotic, N2 – NH3 or NH4+, makes N available, nitrogen fixing bacteria in soil or water
  2. nitrification: NH3 or NH4+ – nitrate, nitrifying bacteria in soil
  3. assimilation: NH3, NH4+, nitrate – amino acids, nucleic acids, plants absorb reactants from soil, assimilate into organic compounds, N now locked into organisms
  4. ammonification: organic N – ammonia, waste products contain N, available for nitrification or assimilation
  5. denitrification: nitrate – N2, returns N to atmosphere