Feeding relationships

• What are the names given to different trophic levels 

  Producers, primary consumers, secondary consumers, tertiary consumers, decomposers
• Different trophic levels: producers 

  Organisms that make their own food using energy from sun (eg plants by photosynthesis)
• Different trophic levels: primary consumers 

  Herbivores that feed on producers 
• Different trophic levels: secondary consumers 

  Carnivores that feed on primary consumers 
• Different trophic levels: tertiary consumers 

  Carnivores that feed on secondary consumers. 
• What are tertiary consumers called 

  The apex predators as they have no predators 
• Different trophic levels: decomposers 

  Bacteria and fungi that break down dead animals bodies and waste, for energy, using enzymes 
• Why are trophic levels used to describe 

  Feeding relationships between organisms 
• How does energy flow from the sun to the producers (first trophic level)

  Form of light- producers convert this light energy into chemical energy and it flows in this form to the next level
• How do you illustrate interactions between organisms 

  With a food chain 
• What else does a food chain show

  The transfer of energy from one organism to the next 
• What is the source of all energy in a food chain 

  Light energy from the sun
• How does energy pass on through a food chain 

  It has to be consumed 
• What energy will pass on through food chains 

  The energy that is made into new cells remains with organism to pass on 
• Why are food chains rarely more than 5 organisms long

  Due to the inefficient loss of energy at each trophic level- the total amount of energy eventually becomes too small to support another trophic level
• What is a food web

  A network of interconnected food chains in an ecosystem 
• What is a herbivore 

  An animal that gets its energy by eating plants 
• What is a carnivore 

  an animal that gets its energy by eating other animals
• What is interdependence 

  How the change in one population can affect others within food web
• What does a pyramid of numbers show 

  How many organisms are at each trophic level of a food chain

  
• What does the width of the box in a pyramid of numbers indicate 

  The number of organisms at that trophic level
• Number of pyramids: general relationship between size of individual organisms and their quantity 

  Generally, the larger an individual organism is, the fewer of them there are 
• What does a pyramid of biomass show

  how much mass the creature at each trophic level would have w/o including all water in organism (their 'dry mass')

  
• Pyramids of biomass: relationship between mass of organisms and going up a food chain

  The mass of organisms has to decrease as you go up a food chain (thus it’s always pyramid shaped)
• What does a pyramid of energy show

  amount of energy contained within the biomass of organisms at each trophic level
• Pyramids of energy: what does the area of each box represent 

  Quantity of energy present 
• Why do pyramids of energy always have a wide base 

  Due to large amount of energy contained within biomass of producers 
• Pyramids of energy: relationship between energy of organisms and going up a pyramid/food chain

  As you move up, quantity of energy decreases as not all energy is transferred to biomass of next trophic level
• What do producers use energy from sun

  To produce glucose from photosynthesis. Then during respiration, glucose is used to produce their own biomass
• What is biomass 

  The mass of living material (A store of chemical energy)
• What happens when primary consumers consume producers 

  They break down the producers biomass (-digestion), and use the chemical energy to increase/sustain their biomass
• What happens when secondary consumers consume primary consumers 

  They break down the primary consumer’s biomass (-digestion), and use the chemical energy to increase/sustain their biomass (and so on)
• What does the consumption of the trophic levels mean 

  As chemical energy is transferred from one trophic level to the next, biomass is also transferred 
• Equation for calculating efficiency of energy and biomass transfers 

  Percentage efficiency transfer= biomass in higher trophic level/biomass in lower trophic level,  x 100
• How much energy is transferred to the next trophic level 

  About 10%
• Reasons why not all energy is transferred to the next trophic level: consumption of organism

  Organisms don’t eat all parts of the organism they’re consuming, eg their bones, which have enrgy
• Reasons why not all energy is transferred to the next trophic level: digestion

  Not all ingested material is digested and absorbed; some is egested as faeces
• Reasons why not all energy is transferred to the next trophic level: movement 

  Some energy is used for movement 
• Reasons why not all energy is transferred to the next trophic level: energy

  Some energy is used to generate heat 
• Reasons why not all energy is transferred to the next trophic level: metabolic processes 

  Some energy is used for metabolic processes