Chapter 13: Ecology

• What is biomass?

  Living or recently dead tissues
• How does biomass change with each trophic level?

  Biomass decreases with each trophic level
• What percentage of biomass is transferred to the next trophic level?

  About 10%
• Why is only about 10% of biomass transferred to the next trophic level?

  Not all organisms or parts are eaten, and some energy is lost in waste
• What role does cellular respiration play in energy transfer?

  It supplies energy needs but transfers much energy to the surroundings
• What is food security?

  Access to sufficient, safe, and nutritious food for all people
• What are some reasons for world hunger?

  Poverty, food wastage, inflated prices, climate change, growing population, war
• How can the movement of food animals be limited to increase food production efficiency?

  By restricting their movement to conserve energy for growth
• How does controlling temperature help in food production efficiency?

  It prevents energy loss for temperature regulation, increasing biomass
• What is a decomposer?

  An organism that breaks down dead organic matter
• How do decomposers absorb nutrients?

  By secreting enzymes on digested organic matter
• What is a detritivore?

  A decomposer that eats dead organic matter and digests it internally
• What are the waste products of decomposers in the decay process?

  Carbon dioxide, water, and nutrients
• What conditions are necessary for decay to occur?

  Temperature, oxygen, and water
• How do high temperatures affect decay?

  They destroy enzymes and proteins responsible for decay
• How do low temperatures affect decay?

  They slow down the rate of decay
• Why is oxygen important for decay?

  Most microorganisms require it for aerobic respiration
• What happens in the absence of oxygen during decay?

  It slows or prevents most forms of decay
• Why is water necessary for decay?

  It is needed for transport and to support reactions inside organisms
• What is the role of microorganisms in sewage treatment?

  They break down human waste to make it safe for the environment
• What are some pollutants present in wastewater?

  Human waste, toxic metal compounds, fertilizers, and pesticides
• What is a compost heap?

  A pile of organic material left for microorganisms to break down
• What does the carbon cycle illustrate?

  How carbon atoms exist within different compounds at different times
• What is the significance of the carbon cycle?

  It shows the movement and transformation of carbon in the environment