Most ecosystems rely on a supply of energy from sunlight.
Energy released from carbon compounds by respiration is used in living organisms and
converted to heat. (Which can not be converted to another form of energy by living organisms)
Light energy is converted to chemical energy in carbon compounds by photosynthesis.
Chemical energy in carbon compounds flows through food chains/webs by feeding.
Energy losses between trophic levels restrict the length of food chains and the biomass of higher
trophic levels.
Skill: Quantitative representation of energy flow using pyramids of energy.
Produce a pyramid of energy using the following information:
1. The total solar energy received by a grassland is 5 x 105 kJ
m-2 y-1.
2. The net production of the grassland is 5 x 102 kJ m-2 y-1 and
its gross production is 6 x 102 kJ m-2 y-1.
3. If only 10% of the total energy is passed to each trophic
level, construct a three tiered energy pyramid for this
ecosystem.
Skill: Quantitative representation of energy flow using pyramids of energy.
Produce a pyramid of energy using the following information:
1. The total solar energy received by a grassland is 5 x 105 kJ
m-2 y-1.
2. The gross production of the grassland is 5 x 105 kJ m-2 y-1
and its net production is 6 x 102 kJ m-2 y-1.
3. If only 10% of the total energy is passed to each trophic
level, construct a three tiered energy pyramid for this
ecosystem.
6 x 102 kJ m-2 y-1
Skill: Quantitative representation of energy flow using pyramids of energy.
Produce a pyramid of energy using the following information:
1. The total solar energy received by a grassland is 5 x 105 kJ
m-2 y-1.
2. The net production of the grassland is 5 x 102 kJ m-2 y-1 and
its gross production is 6 x 102 kJ m-2 y-1.
3. If only 10% of the total energy is passed to each trophic
level, construct a three tiered energy pyramid for this
ecosystem.
60 kJ m-2 y-1
6 x 102 kJ m-2 y-1
Skill: Quantitative representation of energy flow using pyramids of energy.
Produce a pyramid of energy using the following information:
1. The total solar energy received by a grassland is 5 x 105 kJ
m-2 y-1.
2. The net production of the grassland is 5 x 102 kJ m-2 y-1 and
its gross production is 6 x 102 kJ m-2 y-1.
3. If only 10% of the total energy is passed to each trophic
level, construct a three tiered energy pyramid for this
ecosystem.
Secondary Consumers
Primary Consumers
Producers
6 kJm-2 y-1
60 kJ m-2 y-1
6 x 102 kJ m-2 y-1
This begins to highlight the problem with our diet, and
how many tertiary and quaternary consumers we eat.
What limits the size of energy pyramids?
Heat is lost in ecosystems, as are biomass and number of organisms as you go up the food chain.
First Step – Do research using the following
terms “Ecocolumn”, “Sealed Mesocosm”,
“Biology In a Bottle” to get ideas. Sketch out a
plan for how you want to construct your
Ecosystem. Remember the nutrients that
need to be cycled through the ecosystems!
Second Step – Gather the materials for
construction of your mesocosm. If you would
like any fish or small invertebrates to live in
your ecosystem, you need to provide them. I
have the following : Gravel, Water Plants,
Water, Soil, Netting, Bottles, Tape, Scissors,
Terrestrial Plants
Third Step – Implement your design! Set up
the mesocosm in a sink (in case it leaks), and
observe the variable you decided to measure
each week!