1. Energy and Ecology

2. Ecosystem Components Producers Basis of an ecosystem’s energy
Autotrophs: perform photosynthesis to make sugars
Chemotrophs: Bacteria which use minerals from deep-sea vents to make energy
Consumers
Heterotrophs: Consumes others for energy
Omnivores, herbivores, carnivores, decomposers, detritivores

3. 4 kcal 40 kcal 400 kcal 4000 kcal 40,000 kcal
Trophic
Levels
4 kcal
40 kcal
Defined: Feeding level of an ecosystem
Trophic levels consist of producers, consumers, and decomposers
~10% of energy is passed to the next level
~90% used by the organism or lost as heat
Food chains contain few trophic levels
400 kcal
4000 kcal
40,000 kcal

4. Food Chains 1st trophic level = Producers
Autotrophs (perform photosynthesis)
Bottom of food chain
Ex: Plants, algae, cyanobacteria

5. Food Chains 2nd trophic level = Primary consumers Feed on producers
Herbivores (plant eaters)

6. Food Chains 3rd trophic level = Secondary consumers
Feed on primary consumers
Omnivores and carnivores

7. Food Chains 4th trophic level = Tertiary consumers
Feed on secondary consumers
Omnivores and carnivores
consumers

8. Food Chains 5th trophic level = Quaternary consumers
Feed on Tertiary consumers
Omnivores and carnivores
consumers

9. What’s wrong with this food chain?
The arrows are pointing the wrong direction.
This implies that the plant eats the grasshopper.

10. What’s wrong with this food chain?
The arrows are pointing the wrong direction.
This implies that the grasshopper eats the mouse.

11. What’s wrong with this food chain?
The arrows are pointing the wrong direction.
This implies that the mouse eats the snake.

12. What’s wrong with this food chain?
The arrows are pointing the wrong direction.
This implies that the snake eats the hawk.

13. Much better…
The arrows show the direction that energy is passed up the food chain.

14. Label the tropic levels in this energy pyramid
Choices:
Primary consumer
Decomposer
Tertiary consumer
Secondary consumer
tertiary consumer
secondary consumer
primary consumer
producer

15. Decomposers Rarely shown on food chains Quaternary consumer
Teriary consumer
Secondary consumer
Primary consumer
producer

16. Decomposers Rarely shown on food chains
Teriary consumer
Rarely shown on food chains
Feed on any trophic level when it dies
Secondary consumer
Primary consumer
producer
Decomposer

17. Decomposers Rarely shown on food chains
Feed on any trophic level when it dies
Detritivores: Feed/ingest dead matter
Decomposers: secrete enzymes to break down dead matter and then absorb the nutrients

18. Defined: Group of interrelated food chains
Webs
Defined: Group of interrelated food chains
This food web is made from dozens of food chains
Arrows show direction energy (nutrients) travel

19. Highlight a food chain from this food web
Highlight a food chain from this food web. Then label each trophic level.
Tertiary consumer
Secondary consumer
Primary consumer
producer

20. Highlight a food chain from this food web
Highlight a food chain from this food web. Then label each trophic level.
Quaternary consumer
Tertiary consumer
Secondary consumer
Primary consumer
producer

21. What could happen if the grasshoppers die out due to pesticide use?
Owl death (less blue jays to eat)
Blue jay death (less spiders to eat)
Spider death (no more grasshoppers to eat)
Squirrel increase (less owls hunting them)

22. YouTube Food Chain Video

23. Review How many trophic levels are in the following food chain?
Apple tree  Worms  Blue Jay  Owl
If the tree in the example above makes 15,000 calories of energy from photosynthesis, how much energy is available for each other trophic level?
In the food chain above, which is the producer?
In the food chain above, which is the primary consumer?
In the food chain above, which is the tertiary consumer?
Which level consumer are herbivores known as?
What is the lowest consumer level possible for a carnivore?
Examine the food web on slide #10. Find a complete food chain that is 6 trophic levels from start to finish.