1. Energy Flow in a Ecosystem
The ultimate source of energy is the Sun!

2. How does energy from the Sun enter the ecosystem?
PHOTOSYNTHESIS - Plants use the Sun’s energy to make sugars.
6CO2 + 6H2O + sunlight  C6H12O6 + 6O2

3. ENERGY IN
AN ECOSYSTEM
Producer (autotroph) = makes its own food through photosynthesis (self-feeder). Ex: grasses, trees, flowering plants, algae
100% of energy available

4. Where does energy made by the producer go?
CELLULAR RESPIRATION - ingested food
is broken down into energy
C6H12O6 + 6O2  6CO2 + 6H2O + energy

5. ENERGY IN AN ECOSYSTEM Primary Consumer (heterotroph) =
eats producers and produces energy through cellular respiration
AKA - Herbivore = PLANT EATER (Ex: zebra, cow)
10% of energy available
Producer (autotroph) = makes its own food through photosynthesis (self-feeder). Ex: grasses, trees, flowering plants, algae
100% of energy available

6. ENERGY IN
AN ECOSYSTEM
Secondary Consumer (heterotroph) = eats primary consumers (cellular respiration)
AKA: Carnivore=MEAT EATER (Ex: tiger, wolf ) Omnivore = PLANT & MEAT EATER (Ex:human, bear)
1% of energy available
Primary Consumer (heterotroph) =
eats producers, and produces energy through cellular respiration
AKA - Herbivore = PLANT EATER (Ex: zebra, cow)
10% of energy available
Producer (autotroph) = makes its own food through photosynthesis (self-feeder). Ex: grasses, trees, flowering plants, algae
100% of energy available

7. Which teeth do you think are meat-eaters?
Which teeth do you think are plant-eaters?
What type of diet do the human teeth indicate?

8. ENERGY IN
AN ECOSYSTEM
Tertiary Consumer (heterotroph) = eats secondary consumers (Ex: owl, shark)
*May be the APEX PREDATOR (top of food chain)
0.1% of energy available
Secondary Consumer (heterotroph) = eats primary consumers (cellular respiration)
AKA: Carnivore = MEAT EATER (Ex: snake, wolf ) OR Omnivore = PLANT & MEAT EATER (Ex: human, bear)
1% of energy available
Primary Consumer (heterotroph) =
eats producers, and produces energy through cellular respiration
AKA - Herbivore = PLANT EATER (Ex: rabbit, cow)
10% of energy available
Producer (autotroph) = makes its own food through photosynthesis (self-feeder). Ex: grasses, trees, flowering plants, algae
100% of energy available

10. Food Chains vs. Food Webs
Food Chain = a sequence of energy transfer as each organism eats another organism.

11. Food Chains vs. Food Webs
An ecosystem is more complex than a simple food chain. Most organisms eat more than one type of food.
Food Web = a complex sequence of energy transfer showing multiple feeding relationships.

12. Why does the population decrease as the trophic levels increases?
Energy pyramids show how each trophic level (step in a food chain) is supported by the previous level.
Why does the population decrease as the trophic levels increases?

13. What about the dead stuff?
Decomposers- Break down dead organisms in an ecosystem and return nutrients to the soil, water, and air Ex: mushroom, shrimp, bacteria

14. SECONDARY CONSUMER (heterotroph / carnivore)
TERTIARY CONSUMER (heterotroph/carnivore)
0.1% of energy available
SECONDARY CONSUMER (heterotroph / carnivore)
1% of energy available
PRIMARY CONSUMER (heterotroph / herbivore)
10% of energy available
PRODUCERS (autotroph)
100% of energy available

15. ENERGY IN
AN ECOSYSTEM