1. Catalyst
Based on the food chain shown, what would most likely happen to the rat population if another predator began eating snakes?
Is the the change in number 1 biotic or abiotic?
What could cause a decrease in the grasshopper population?

2. Agenda Catalyst Energy Pyramids PowerPoint Making an Energy Pyramid
Energy Pyramid Project

3. Objectives
SWBAT distinguish between producers and consumers and autotrophs and heterotrophs
SWBAT identify the category of organisms and relative amount of energy represented by each trophic level of an energy pyramid
SWBAT explain how and why energy changes from the base to the top of an energy pyramid.

4. Energy Pyramids
Biology

5. Organisms and Energy
All organisms need energy to survive, and they receive energy from the food that they produce or consume

6. Energy Flow
For an ecosystem to exist, there must have constant flow of energy between the organisms of that ecosystem

7. Energy Pyramids
Scientists model the flow of energy in an ecosystem with an energy pyramid
Contains different levels of organisms known as trophic levels

8. To take notes…
Fill in the example energy pyramid

9. Producers The first trophic level is at the bottom of the pyramid
Organisms at the bottom of the energy pyramid are known as producers
Producers are autotrophs—organisms that use energy from the sun to produce food

10. Producers What are some examples of producers/autotrophs? Trees Grass
Berries
Nuts
Algae
Phytoplankton

11. Consumers All other organisms in the energy pyramid are consumers
Consumers are heterotrophs—organisms that obtain energy from the food they consume

12. Primary Consumers
Above producers in the pyramid are primary consumers.
2nd trophic level
These are herbivores—organisms that consume only plants.

13. Primary Consumers
What are some examples of primary consumers/herbivores?
Insects
Rabbits
Deer
Mice
Small fish

14. Secondary Consumers
Above the primary consumers in the pyramid are secondary consumers.
These are carnivores—organisms that consume other animals.

15. Secondary Consumers
What some examples of secondary consumers/carnivores?
Frogs
Snakes
Large fish
Foxes

16. Tertiary Consumers Above secondary consumers are tertiary consumers.
These may be carnivores or omnivores—organisms that consume both plants and animals

17. Tertiary Consumers What are some examples of tertiary consumers? Hawks
Eagles
Bears
Humans
Sharks

18. Energy in a Pyramid
So why do scientists use a pyramid to represent energy in an ecosystem?
How does a pyramid change from bottom to top?
It gets smaller!
So does the amount of energy in an ecosystem from producers  high level consumers

19. Energy Changes
The bottom of the energy pyramid (producers) contains the greatest amount of energy.
100% of energy originally present in the ecosystem
The top (tertiary consumers) contains the least amount of energy.
~0.1% of initial energy
Energy is lost as heat between trophic levels
~90% lost as heat between each level
Only 10% of available energy transferred to next level

20. Summary

21. Energy Pyramid

22. Question…
If there is less energy available at higher trophic levels, will there be more organisms or fewer organisms as you go up?

23. Number pyramids + Biomass Pyramids
Number pyramids show the population decreasing at higher levels
Biomass pyramids show how much food an organism needs to consume to meet its needs.

24. >> Check for understanding
A biologist finds that there is far more algae (a producer) in an ecosystem than anchovy. What is the reason for this?
Anchovy is a second-order producer, so there is less energy available than there is for producers.

25. Energy Water Demo

26. Example: Copy the chain and answer questions in your notes
Grass  Insects  Rodents  Owl
Create an energy pyramid.
Label each level with the appropriate term and trophic level.
Put the names of each organism in the appropriate level.

27. If there is 1500kcal of energy in the grass, how much energy will be available for the insects? 1500kcal x 0.10 = 150kcal

28. Exit Ticket
What level on the energy pyramid shown has the greatest amount of energy to transfer to the next level?
What are the secondary consumers in this example, and are they autotrophs or heterotrophs?
Which level receives the least amount of energy from the producers?
Why does the amount of energy decrease as you move from the bottom to top of an energy pyramid?