1. Energy Flow in Ecosystems

2. All energy on Earth depends on the Sun
All energy on Earth depends on the Sun. Organisms capable of using the sun’s energy directly are called Producers. Plants & Algae are Producers.

3. Producers make their own food; they are autotrophs.
They do this through Photosynthesis:
Water + Carbon Dioxide  Glucose + Oxygen

4. Photosynthesis needs:
Sunlight
Water
Carbon Dioxide
And, inside
plant cells:
Chlorophyll
Chloroplasts

5. These are the Consumers
Producers support the animals that can’t make their own food – heterotrophs.
These are the Consumers
Animals that eat the producers are Primary 1o Consumers.

6. 1o Consumers = Herbivores

7. In turn, they support the next level, the Tertiary 3o Consumer.
These 1o Consumers are the food source for other heterotrophs, the Secondary 2o Consumers.
In turn, they support the next level, the Tertiary 3o Consumer.
These organisms can be carnivores or omnivores.

8. Carnivore or Omnivore?

9. There are some consumers which are only predators, and never prey.
These are the Top Consumers, and they are usually strict carnivores, although some are omnivores.

10. Top Consumers

11. Whether an organism is a producer or consumer is part of defining its Trophic Level.
Trophic Levels are categories of organisms based on how they get their energy.

12. If we link organisms by the rank of their Trophic Level, we get a Food Chain:

13. If we link several Food Chains, we get a Food Web:

14. If we link several Food Chains, we get a Food Web:

15. Food webs include specialist consumers, such as:
Decomposers
Scavengers
Symbionts

16. With every step in a food chain, some energy is lost.
This is often as body heat, so in a way, it’s not ‘lost’… it’s helpful
But that energy can’t provide nutrition to others, so that way, it’s ‘lost’
Food Pyramids illustrate this

17. Food Pyramids

18. Food Pyramids measure T.E.

19. In any ecosystem, many producers support only a few top consumers.

20. Bioaccumulation or Biomagnification is a problem in ecosystems because of energy flow.
Lower level consumers get amounts of a pollutant that is not toxic, but top consumers get very toxic effects.

21. Bioaccumulation: Arctic Food Chain

22. Bioaccumulation: Great Lakes
Food Chain

23. Bioaccumulation: Bald Eagle
&
Peregrine Falcon