Science 10
2.1
ENERGY FLOW IN ECOSYSTEMS
Learning Targets
I can
 Define primary, secondary, and tertiary consumer
 Define herbivore, carnivore, omnivore, and detrivore
 Use a food web to explain how the energy is transferred throughout an
ecosystem
 Use a food pyramid to explain how consumed energy is used
Where do we get energy?
Energy does not stay in one place in an ecosystem – it move through the
ecosystem due to the interactions of different organisms with each other
Each organism
Obtains food energy from the ecosystem
Contributes energy back to the ecosystem
Called ___________
Levels
1. Producers
Produce __________ using sunlight and _____________
a. Usually Plants
2. Consumers
Consume ____________ to gain energy. There are 3 types of consumers:
I. Primary Consumers
a. Feed on _________________ (___________)
I.e. Grasshoppers, deer, zooplankton
II.
Secondary Consumers
a. Feed on _________________ (___________)
I.e Frogs, song bird, some fish
III.
Tertiary Consumers
a. Feed on _________________ (___________)
b. Top of the food chain
I.e. Hawks, people, bears
**Some animals act as consumers at different levels**
i.e. Bears -
Primary consumer (berries)
Secondary consumer (fish)
Called _________________
Any other species come to mind?
The breakdown organic waste material and dead organisms is known as
_______________
(it is also called biodegradation)
Done by detrivores (insects and animals that feed on ____________
_______________) or decomposers (fungi or bacteria)
Food Chains & Webs
Food Chains show the movement of nutrients within an ecosystem from one
trophic level to the next
A trophic Level is a _________ in the _________ __________
Example: grass  mouse  snake  hawk
Food Webs
Many animals belong to more than one food chain
A food web indicates feeding relationships within an ecosystem
Example:
Food Pyramids
When a snake eats a mouse, not all of the energy from the mouse is stored
and passed on to the hawk that eats the snake
 Most is used for the chemical reactions that sustain life
 Some is lost as undigested matter
 Only a small amount (10%) is converted into biomass (__________
_________) that is transferred to the next trophic level
 Food pyramids show the loss of energy between trophic levels
 Also called ecological pyramids
Homework
Energy Flow Worksheet (BC Science 10 SWB pg. 15-18)