Energy transfers

• What is a producer ?

  The plant that makes food by photosynthesis
• What is a primary consumer?

  Animals that eat the producer
• What is a secondary consumer?

  Usually eats the primary consumer and are carnivores
• What is a tertiary consumer?

  It eats secondary consumers
• What is a quaternary consumer?

  It eats tertiary consumers
• What is an omnivore?

  An organism that eats both plants and meat
• What is a trophic level?

  The position occupied by a group of organisms in a food chain
• What is a food chain?

  A description of a feeding relationship between organisms
• What is a food web?

  A network of many food chains linked together
• What is a carnivore?

  An animal that eats other animals
• Why is radiation from the Sun important for ecosystems?

  It is the main source of energy for all living things
• How do producers use solar energy?

  They capture it during photosynthesis to make new biomass
• What happens to biomass when primary consumers eat it?

  It is broken down during respiration to release chemical energy
• What do animals use the energy from respiration for?

  For movement, maintaining body temperature, growth, and reproduction
• What is biomass?

  The total mass of living material or the chemical energy stored in the organism
• How can biomass be measured?

  In terms of mass of carbon or dry mass of tissue per given area
• Why is dry mass measured for biomass?

  To avoid variations in mass due to water content
• How is dry mass measured?

  A sample of tissue is dried in an oven and weighed until the mass becomes constant
• What are typical units for measuring dry mass?

  g m$-2$ or kg h$-2$
• How can biomass be recorded for a harvest grown over time?

  As kg m$-2$ y$-1$
• How can a calorimeter estimate the mass of carbon in biomass?

  By burning the biomass and measuring the energy given off as heat
• What is a benefit of using pyramids of energy over biomass?

  They are more accurate as they account for different energy storage in organisms
• What is a limitation of using pyramids of biomass?

  They can only use a small sample which may not be representative
• What is a limitation of using pyramids of energy?

  Data can be difficult to collect and only represents a given area at one time point
• What is the total mass of living material in an ecosystem called?

  Biomass
• What is the main source of energy for all ecosystems?

  Solar energy/radiation
• What are the organisms called which are at the start of all food chains?

  Producers
• What is most of the energy harnessed by the sun in plants used for?

  To make sugars used for respiration
• What are the two ways biomass can be measured?

  As dry biomass or as mass of carbon
• How can a calorimeter be used to measure biomass?

  It burns the biomass and calculates how much energy is present by measuring the temperature increase of a known volume of water
• What is a benefit of using pyramids of energy over biomass?

  They are more accurate as two organisms of the same biomass could store different amounts of energy
• What is a limitation of using pyramids of biomass/energy?

  Waste inside animals will be included
• What is a limitation of using pyramids of biomass/energy?

  If samples are made at a single point in time, biomass/energy may vary with season
• Chemosynthesis


  The process by which some bacteria make their own food using chemical energy instead of sunlight.
• Plants

  Examples: trees, grasses, crops, flowers, and other green organisms that make their own food through photosynthesis.
• Algae


  Simple aquatic plants that live in water and make their own food through photosynthesis.
• What is the definition of productivity in an ecosystem?

  Productivity is described as the rate of generation of biomass in an ecosystem.
• How is productivity usually measured?

  Productivity is usually measured in units of mass per area per unit time (g/m²/y).
• What is gross primary production (GPP)?

  GPP is the total amount of chemical energy converted from light energy by plants in a given area.
• Why do plants not convert all light energy into chemical energy?

  Some light energy is reflected, transmitted through the leaf, is the wrong wavelength, or hits parts of the plant that cannot photosynthesize.