Energy transfer between trophic levels Flashcards
Where is energy stored in an organism?
the biomass of the organism
How is energy transferred to the next trophic level?
by feeding
What forms can energy be transferred in?
biomass
transferred as heating to the environment
Which form of energy is less useful?
heating, as it can’t be transferred to biomass
Describe the energy transfers to and from the producer in a food chain (plants) (3)
energy is transferred to the plant by light during photosynthesis
energy from respiration is transferred to the surroundings by heat
energy stored in new plant biomass can be transferred to herbivores as food
Describe the energy transfers to and from an animal in a food chain (4)
energy is stored in biomass as food, and is consumed
energy from respiration is transferred to the surroundings by heat
energy stored as new animal biomass which can be transferred to carnivores in their food
energy stored in substances in faeces and urine
pyramid of biomass
a diagram that shows the amount of biomass (as g/m[2]) at each trophic level in an ecosystem
the producer level is the bottom bar, and the other bars are the trophic levels in order
Describe the size of the bars in a pyramid of biomass as you go up
the amount of biomass at each trophic level along the food chain gets smaller, as some energy at each level is transferred by heating the environment
How many trophic levels do food chains usually have and why?
no more than 4 or 5
there is not enough biomass in the top level to provide the energy needed by another trophic level
biomass of an organism
the mass of its body tissue
1900 kJ of energy from the Sun’s light falls on a hectare of grass in a year. The energy stored in the biomass of the grass is 20700 kJ. Find the percentage of the energy transferred by light to the plant’s biomass as a result of photosynthesis. [2]
1900/20700 x 100 = 91.8%
Identify two ways that energy is transferred from an animal to the environment [2]
as chemical energy in faeces and urine
as heat energy from respiration
Identify one way that energy is transferred to a plant fro the environment [1]
as light energy from sunlight
It has been suggested that food chains in tropical rainforests contain more trophic levels than those in temperate areas (e.g. the UK) because rainforests receive more energy transferred by light from the Sun.
Explain the reasoning behind this suggestion. [3]
if more energy enters the system as light energy converted to chemical energy by plants, then there will be more energy in every equivalent trophic level of a tropical food chain than in a temperate food chain
there may be enough energy in the tropical trophic level equivalent to the top temperate trophic level to support a higher trophic level, producing a longer food chain
