1. Energy Flow in an Ecosystem

2. The Start of Energy Flow
Begins with the SUN
Photosynthesis
6CO2 + 6H2O + sunlight & chlorophyll  C6H12O6 + 6O2
carbon dioxide
water
glucose (sugar)
oxygen

3. How do organisms obtain energy?
PRODUCERS (autotrophs)
make their own food.
Ex: plants, algae
Consumers (heterotrophs)
Eat producers and other organisms

4. Primary Consumers (first order heterotrophs) - Eat producers
Types of Consumers
Primary Consumers (first order heterotrophs) - Eat producers
- Ex: deer, rabbit

5. Types of Consumers Secondary Consumers (second order heterotrophs)
Eat primary consumers; carnivores
Ex: fox, mouse

6. Tertiary Consumers (third order heterotroph)
Types of Consumers
Tertiary Consumers (third order heterotroph)
Eat the secondary consumers; carnivores
Ex: wolf, snake

7. Decomposers
Decomposers – Break down the remains of dead organisms Ex: bacteria, worms, fungi
Known as “nature’s recyclers”

8. Energy Flow in an Ecosystem
Food Chains – the arrows represent the flow of energy from one organisms to the next
Hawk
Mouse
Grass
Notice the direction of the arrow!

9. Energy Flow in an Ecosystem
Food Webs – represent the many possible pathways energy can flow in an ecosystem

10. Energy Flow in an Ecosystem
Energy Pyramids - represent the loss of energy from 1 level to the next
Ex: There is less energy as you go up the pyramid
10 Kcal
Hawk
100 Kcal
Snake
*Only 10% of the energy passes to the next level.
*90% of the energy is used or lost at each trophic level
1,000 Kcal
Rabbit
Grass
10,000 Kcal

11. Where does the energy go?
Most of the energy passed between trophic levels is used by the organism, and some of the energy that is lost at each level is lost in the form of HEAT.

12. Energy Pyramids

13. Brain Pop – Energy Pyramids

14. Energy Pyramid Examples
In the food chain
grass  mouse  snake  eagle
if a mouse eats the grass and then a snake eats the mouse, about how much energy from the grass is stored in the mouse?

15. Energy Pyramid Examples
2. How much energy is available to the organism in level C?
a. all of the energy in level A plus the energy in level B
b. all of the energy in level A minus the energy in level B
c. some of the energy in level B
d. all of the energy in level B