Energy

• What are producers?

  Photosynthetic organisms that manufacture organic substances
• What are consumers?

  Organisms that get energy from feeding on others
• What distinguishes primary, secondary, and tertiary consumers?

  Primary eat producers, secondary eat primary, tertiary eat secondary
• What are decomposers?

  Organisms that break down dead materials into simpler ones
• What role do decomposers play in ecosystems?

  They release minerals and elements for plant absorption
• What is a food chain?

  Feeding relationship where producers are eaten by consumers
• What is each stage in a food chain called?

  Trophic level
• What is a food web?

  Many food chains linked together in a habitat
• What is biomass?

  Total mass of living material in a specific area
• Why is it difficult to measure biomass?

  Water makes fresh biomass readings unreliable
• How can you measure dry biomass?

  Using calorimetry to estimate chemical energy
• Why is not all of the sun's energy absorbed by plants?

  90% is reflected back into space by clouds
• What is gross primary productivity (GPP)?

  Rate at which plants capture and store energy
• What is net primary productivity (NPP)?

  Rate of useful energy produced by plants
• Why does energy decrease as you go down the food chain?

  Not all organisms are consumed, energy is lost
• Why do most food chains only have four trophic levels?

  Insufficient energy to support larger populations
• Why is nutrient cycling needed within ecosystems?

  Nutrients need to be recycled due to limited supply
• What is a saprobiont?

  Microorganism that feeds on dead organic matter
• Why are saprobionts important?

  They break down larger molecules into simpler forms
• Describe the process of nutrient cycles.

  Nutrients absorbed by producers, passed to consumers
• Why is phosphorus important?

  It is essential for ATP and nucleic acids
• Where do dissolved phosphate ions exist?

  In oceans, lakes, and soils
• What are the ways phosphate is released?

  Through animal excretion and erosion of rocks
• What are the ways phosphate is taken up?

  Absorbed by plants and sediments into rocks
• What are mycorrhizae?

  Associations between plant roots and fungi
• What happens during ammonification?

  Ammonia forms from decomposing organic matter
• What happens during nitrification?

  Nitrifying bacteria convert ammonium to nitrate
• What happens during nitrogen fixation?

  Nitrogen gas is converted to ammonia by bacteria
• What happens during denitrification?

  Anarobic bacteria convert nitrates to nitrogen gas
• What are the effects of fertilizers?

  Reduced species diversity and eutrophication
• What happens during eutrophication?

  Fertilizers cause algae growth, blocking sunlight