1. How Ecosystems Work

2. How Ecosystems Work Big Ideas
Energy is transferred from the sun to producers
Producers then transfer the energy to consumers
Inefficient energy transfer has an effect on community structure

3. Life Depends ENERGY, LOTS OF ENERGY…from the Sun
Average Star
93 million miles away
Nuclear Fusion
No Sun, No Life

4. Life Depends on the Sun
ALL organisms need a constant supply of energy or they die
Why do plants grow upwards?

5. What is photosynthesis?
CO2 + H2O + Sunlight  O2 + C6H12O6
The process of converting carbon dioxide, water and sunlight into oxygen and glucose.
(In plants, algae, some bacteria)
Occurs in chloroplasts

6. From Producer to Consumer
Producer: an organism that makes it own food
Plants
Autotrophs, self-feeders
Use sunlight
Base of all food chains

7. What role do Autotrophs (Producers) Play?
Gather the energy from the sun and turn it into food via photosynthesis. Lichens are an example.

8. Phytoplankton get no credit

9. From Producer to Consumer
Consumer: gets it energy by eating producers or other consumers
Heterotrophs
Indirectly solar powered

10. What role do Heterotrophs (Consumers) play?
Heterotrophs eat other organisms to obtain their energy.
Stored energy in food is extracted with or without oxygen.

11. Types of Consumers Herbivore: eats only producers (vegetarian)
Cows, sheep, deer, grasshopper, mice, rabbits

12. Herbivore

13. Types of Consumers Carnivore: eats other consumers
Lion, hawks, snakes, alligator, toothed whales

14. Carnivore

15. Types of Consumers Omnivore: eats both producers and consumers
Bears, pigs, raccoons and most humans

16. Omnivore

17. Types of Consumers Decomposer: breaks down dead decaying organisms
Critical to ecosystem health
Returns nutrients
Fungus, bacteria

18. Detritivores and decomposers: recycle nutrients within the ecosystem by breaking down nonliving organic matter

19. Decomposer

20. How do Organisms Use Energy
Most organisms spend large amounts of time/energy in search of food and a mate.

21. How do organisms get the energy from the food (glucose)? Two ways.
Aerobic Respiration – use oxygen to extract energy from glucose
Anaerobic Respiration – oxygen is NOT used to extract energy from glucose

22. Cellular Respiration (Aerobic Respiration) allows organisms to use the energy store in glucose.

23. Aerobic Respiration aka “Cellular Respiration”
Formula
C6H12O6 + O2
CO2 +
H2O +
ATP

24. Photosynthesis & Cellular Respiration
In photosynthetic organisms, the processes of photosynthesis and cellular respiration work together.
The products of one can be used for the other.

25. Energy Transfer
Each time one organism eats another, energy is transferred
Ecosystems are all about energy flowing from one organism to another

26. Energy Transfer Who are the producers? Consumers? Herbivores?
Carnivores?
Omnivores?
Decomposers?
Where does the energy start?

27. How does energy flow through an ecosystem?
A food chain is a series of steps in which organisms transfer energy by eating or being eaten (arrows?)
All food chains have a producer on bottom, which supplies each level above with food
Energy flows in one direction through a Food Chain.
Each step in a food chain is called a trophic level.

28. Energy Transfer
Food Chain: sequence in which energy is transferred from one organism to another
Starts with producers
Energy flows in one direction

29. Food Web A food web shows the various food chains within an ecosystem.
Can you describe one food chain within this food web?
What is missing from this food web?

30. Energy Flow
Food Web: shows many feeding relationships that are possible in a ecosystem
More complex and realistic

32. Energy Flow
Trophic Level: each step which energy is transferred

33. How is energy monitored in a food chain?
Energy Pyramid track available energy in a food chain. Only 10% of the available energy is passed from one trophic level to the next.

34. Energy Pyramid 1 unit of energy 10 units of energy 100 units of energy

35. Energy Flow At each trophic level about 90% of energy is lost
Cellular respiration
Lost to heat body and carry out living

37. Energy Flow
Why are there fewer organisms at the top? (Why fewer bears than the fruit they feed on)
Why aren’t there more than 4-5 trophic levels in a energy pyramid?

38. Review
Energy is transferred from the sun to producers through the process of photosynthesis
Consumers use the glucose made by producers for energy
Food webs show more complex & realistic feeding relationships in a ecosystem
Energy pyramids track available energy in a food chain. Only 10% of the available energy is passed from one trophic level to the next.