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The Energy Pyramid
Let's build the energy pyramid.
I go to Following the Energy Trail
and find the table that shows the Primary Productivity per
Square Meter per Year for my biome. I find my biome and see
how many Kilocalories each square meter can produce in a year.
Build Your Pyramid Diagram
Level One -- Edible Calories
Produced by Plants
This is where you use the number that you just found. I'm
using the Polar Tundra. Summer is short, only six to ten
weeks, and temperatures are below freezing for six to ten months
of the year. This makes for a very short growing season. I am
hoping that the plants can produce 600 Kilocalories of food per
square meter. This is not even 2 KiloCalories a day, but most
days the plants are paralyzed by the cold, so they are doing
the best that they can.
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600 Kilocalories per Square Meter Per Year available
for herbivores to eat |
Level Two -- Edible Calories
Produced by Herbivores
Herbivores use about 90% of the Kilocalories that
they eat for breathing, digesting, warming their bodies, running
around, and reproducing. This leaves about 10% of the Kilocalories
that they eat for building their bodies, which are mostly edible
protein. The next level of the pyramid =
10% of 600 Kilocalories = 0.10 * 600 = 60 Kilocalories
Herbivores produce 60 Kilocalories of animal body per
square meter per year
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600 Kilocalories per Square Meter Per Year available
for herbivores to eat |
Level Three -- Edible Calories
Produced by Carnivores Eating Herbivores
Carnivores really have to work to eat meat.
They can capture 60 Kilocalories per square meter
of ground by eating the herbivores, but they can only transfor
about 10% of the Kilocalories that they eat into the structures
of their own bodies.
10% of 60 Kilocalories = 0.10 * 60 = 6 Kilocalories
First level predators (carnivores ) produce six Kilocalories
of biomass (their actual bodies) per year per square meter.
Herbivores produce 30 Kilocalories per square meter per
year
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600 Kilocalories per Square Meter Per Year available
for herbivores to eat |
Make this into a graphic:
or
© 2000. Elizabeth Anne Viau. All rights
reserved. This material may be used by individuals for instructional
purposes but not sold. Please inform the author if you use it
at eviau@earthlink.net.
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