1. Pyramids Of Energy
D. Crowley, 2008

2. Wednesday, April 26, 2017
Pyramids Of Energy

3. Big Mac Where does the energy in a Big Mac come from?
There is no energy in a big Mac – that is why they are bad for you
It comes from the sugar in the burger sauce
It comes from the cows that make the burger
It comes from the green parts because they are healthier
It comes from the sun

4. Big Mac
All the energy within our food originates from the sun – transferred through food chains...
It comes from the sun

5. Review: Food Chains and Webs
Food chains show a single flow of energy through a ecosystem.
These are simplified: nature is much more complicated!
Producer Primary Consumer Secondary Consumer Tertiary Consumer

6. Review: Food Chains and Webs
A Food Web gives a better idea of how energy flows
But it is very messy and hard to read!
There is a better way to visualize the flow of energy through a system

7. Pyramid Of Energy
We organize food webs into trophic levels of an energy pyramid
Energy flows up the pyramid!
Each level is determined by where (who) an organism gets its energy from.
In other words…who do they eat?
These are called “trophic” levels.
Trophic = “feeding.”

8. Pyramid Of Energy
The lowest level is getting their energy from the sun.
In other words, they make their own food
Called “autotrophs.”
Auto = “Self”
Label the correct level on the
pyramid.
Which organism is an autotroph?
The Oak Tree

9. Pyramid Of Energy The next level gets their energy from the producer.
Called “heterotrophs.”
Hetero = other
Since all the levels above producer eat others, we call them all “Heterotrophs.”
Label the correct sections of the pyramid
Which organisms are heterotrophs?
Sparrow hawk, Bluetit and caterpillar!

10. Pyramid Of Energy
The last type of organism gets their energy from things that have died.
We call the organisms that get their energy from other dead organisms…
Decomposers!
Listed outside the pyramid
Draw a decomposer
on the pyramid

11. Pyramid Of Energy

12. Pyramid Of Energy Why is each level smaller than the level below it?
Not all of the energy that was taken in by the lower level is available to the level above.
It is lost as:
Heat (into space).
Waste (poop)
Approximately 90% is lost at each
level.

13. Pyramid Of Energy How much is available to level above? Units: 10%
This is called the 10% Rule
Units:
Measured in kCal (kilocalories)
or KJ (kilojoules)

14. Autotroph: 123,000 KJ Pyramid Of Energy Units: Joules or Calories
3rd Order
Heterotroph:
123 KJ
2nd Order
Heterotroph :
1,230 KJ
1st Order Heterotroph:
12,300 KJ
Autotroph: 123,000 KJ

15. Pyramid Of Energy
Label the trophic levels and add the values to each level: Trophic Level 3rd order Heterotroph 53kCal 2nd order Heterotroph 530kCal 1st order Heterotroph 5300kCal Autotroph 53000kCal
Where does the rest go??
90% of each level, lost as heat

16. Pyramid of Numbers
The population of each organism in a food chain can be shown in a sort of bar chart called a pyramid of numbers
The more organisms there are, the wider the bar.
The producer in the food chain always goes at the bottom of the pyramid of numbers
E.g. clover  snail  thrush  hawk

17. Pyramid Of Number
Pyramids of number show how many organisms there are in a habitat
What might a pyramid of number for the food chain below might look like ? -
If there were 200 grass plants; 25 voles; and 1 barn owl

18. Pyramid Of Number
Pyramids of number show how many organisms there are in a habitat
However they may not always look like classical pyramids: -
Here there are much more caterpillars than there are oak trees which is why the pyramid is oddly shaped.

19. Pyramid Of Biomass Biomass means the amount of biological material.
It is measured as total dry mass of organisms in a given area (all the water is taken out… dehydrated).

20. Pyramid Of Biomass
The pyramid shows the amount of biological material at each trophic level.
This means the oak tree has the most biological material while the sparrowhawk has the least.
Units: g/m2, lbs/m2, kg/m2

21. Pyramid Of Biomass
The conversion of biomass from one trophic level to the next is inefficient-
From producer to primary consumer.
From primary consumer to secondary consumer
From secondary consumer
to tertiary consumer, etc.

22. Pyramid Of Biomass Why? Energy is lost as heat.
Matter (biomass) is lost as waste.