1. Energy Flow Through an Ecosystem
Food Chains, Food Webs, Energy Pyramids

2. Energy Flow in Ecosystem
Begins with the SUN
Photosynthesis
6CO2 + 6H2O + sunlight & chlorophyll C6H12O6 + 6O2

3. Chemical reaction by which green plants use water and carbon dioxide and light from the sun to make glucose.
ENERGY is stored in glucose; glucose is stored as starch.

4. PRODUCERS Organisms that can make glucose during photosynthesis
PRODUCERS Organisms that can make glucose during photosynthesis. Use most of the energy they make for themselves. Use cellular respiration to supply the energy they need to live.

5. CELLULAR RESPIRATION The chemical reaction that releases the energy in glucose.
6O2 + C6H12O6 -->  6H2O + 6CO2 + energy

6. The energy that is not used by producers can be passed on to organisms that cannot make their own energy.

7. CONSUMERS Organisms that cannot make their own energy.

8. 1st Order (Primary) Consumer
Consumers that eat producers to get energy.
Are herbivores (plant-eaters)
Most of the energy the primary consumer gets from the producer is used by the consumer
Some of the energy moves into the atmosphere as heat.

9. 1st Order Consumer Some energy in the primary consumer is not lost to the atmosphere or used by the consumer itself, so… Leftover energy is available for another consumer.

10. 2nd Order (Secondary) Consumer
A consumer that eats another consumer for energy.
May be a carnivore or a omnivore
May be a predator or scavenger
Most of the energy it gets from the 1st order consumer is used by the secondary consumer.
Some energy is lost as heat but some energy is stored and can be passed on.

11. 3rd Order (Tertiary) Consumer
A consumer that eats a consumer that already ate a consumer.
May be a carnivore or a omnivore
May be a predator
May be a scavenger

12. Omnivores Consumers that eat producers & other consumers
Omnivores eat plants and animals

13. Predator vs. Prey Predators Consumers that hunt & kill other consumers. Prey The animals that are hunted & killed.

14. Scavengers Consumers that eat other consumers that have already died.

15. Food Chain Used to show the transfer of energy from sun to producer to primary consumer to secondary consumer to tertiary consumer. Turn to p. 445

16. ENERGY PYRAMID Another way of showing the transfer of energy in an ecosystem is the

17. Energy Pyramids Show
That the amount of available energy decreases down the food chain
It takes a large number of producers to support a small number of primary consumers
It takes a large number of primary consumers to support a small number of secondary consumers

19. Energy Loss & 10% Rule

20. Food Webs Are interconnected food chains
Third-level
Consumers
Bobcat
Hawk
Second-level
Consumers
First-level
Consumers
Weasel
Desert
Cottontail
Woodrat
Producers
Prickly Pear
Cactus
Mesquite
Are interconnected food chains
They show the feeding relationships in an ecosystem
10% rule: Only 10% of the energy available at one level is transferred to the next level.

21. Food Webs

22. Aquatic Food Web

23. Second-level consumer
Energy Flow Summary
Sunlight
First-level consumer
Third-level consumer
Producer
Second-level consumer

24. Summary Questions
Name the three energy roles of organisms in an ecosystem. How does each type of organism obtain energy?
How does the amount of available energy change from one level of an energy pyramid to the next level up?
Name and define the four types of consumers.
What is the source of energy for most ecosystems?
What are food webs a more realistic way of portraying ecosystems than food webs.