1. 3.3 Energy Flow in Ecosystems
Ecology

2. POINT > Identify ways we conceptualize energy flow through ecosystems
POINT > Describe food chains
POINT > Describe food webs
POINT > Describe ecological pyramids

3. POINT > Describe food chains
A food chain is a series of steps in which organisms transfer energy by eating and being eaten
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

4. POINT > Describe food chains
Each step in a food chain is called a trophic level
The first level is always a producer
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

5. POINT > Describe food chains
Each step is called a trophic level Consumers make up all the other levels Primary consumer (First Level) Secondary consumer (Second) Tertiary consumer (Third) Quaternary consumer (Fourth)
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

6. POINT > Describe food chains
Arrows always point to where the energy is going
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

7. POINT > Describe food chains
Ex. A marine food chain:
Phytoplankton: A mix of algae, the primary producers
Zooplankton: A diverse mix of protists and tiny animals consuming the phytoplankton
Phytoplankton
Zooplankton
Small
Fish
Large
Fish
Whale
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

8. WB CHECK: Ex. A marine food chain:
Phytoplankton
Zooplankton
Small
Fish
Large
Fish
Whale
What trophic level are the “small fish”?
Which organisms are the tertiary consumers?
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

9. POINT > Describe food webs
Food webs are more complicated networks of feeding interactions composed of many food chains
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

10. POINT > Describe food webs
Ex. Antarctic Ecosystem
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

11. Food Web Everglades Marshland Ecosystem
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.
Everglades Marshland Ecosystem

12. POINT > Describe ecological pyramids
Ecological pyramids show the relative amount of energy or matter contained at each trophic level in a food chain or web
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

13. POINT > Describe ecological pyramids
Energy Pyramid:
Shows relative amount of energy available at each trophic level
Tertiary
Consumer
Secondary
Consumer
Primary
Consumer
Producer
Light
Chemical
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

14. POINT > Describe ecological pyramids
Energy Pyramid:
On average, only about 10% of energy available to a level is passed to the next level
Tertiary
Consumer
0.1%
Secondary
Consumer 1%
Primary
Consumer
10%
Producer
Light
100%
Chemical
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

15. POINT > Describe ecological pyramids
Energy Pyramid:
About 90% gets used up by the organism for various functions or is lost as heat
Heat
Tertiary
Consumer
Maintaining Homeostasis
0.1%
Heat
Secondary
Consumer 1%
Heat
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.
Primary
Consumer
10%
Heat
100%
Producer
Light
Chemical

16. WB CHECK:
How much energy is lost between trophic levels?
What are the primary producers in a marine food web?

17. POINT > Describe ecological pyramids
Biomass Pyramid:
Shows relative amount of living organic matter at each level
Usually given as a mass per area
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

18. POINT > Describe ecological pyramids
Numbers Pyramid:
Shows relative number of individuals at each level
Review the prefixes “bio” and “a.” Review “habitat” if needed.
Examples of biotic factors: moose, shrubs, humans, dogs, flowers etc.
Examples of abiotic factors: water, soil, rocks, air, etc.

19. WB CHECK:
In a biomass pyramid, where is the greatest amount of biomass, the top or bottom?
True or False:
A population of large predators has more total biomass than a population of smaller prey animals.

20. Homework
Read pages Assess Page 78 #1-2 Workbook pages