1. Food Chains and Food Webs

2. DO NOW TUESDAY
Create a food chain using the following organisms:

3. TODAY’S PLAN TODAY’S DO
To describe the transfer of energy in relationships.
TODAY’S DO
We will watch a video: “Of Ice and Fire” and answer questions about the video.
We will write some definitions of food chain vocabulary on our glossary sheet.

4. DO NOW THURSDAY
Observe both the aquatic and terrestrial ecosystem for your group. Person 2 in each group should fill out the information for your ecosystem only.
DO NOT MOVE THE ECOSYSTEMS from the place where they have been put because we need to observe the natural behaviors of these animals.

5. TODAY’S PLAN TODAY’S DO
To describe the transfer of energy in relationships.
TODAY’S DO
We will complete the Pond Ecosystem Gizmo with your table partner.
This Gizmo must be completed today.
You will receive a grade for this Gizmo.

6. DO NOW FRIDAY Create a food chain using the following organisms:
Raccoon
Algae
Small fish
Phytoplankton
Big fish

7. TODAY’S PLAN TODAY’S DO
To describe the transfer of energy in relationships.
TODAY’S DO
We will discuss food chain and food web vocabulary.
You will create a food web for the Mono Lake Ecosystem.
You will draw the food web and label each organism in the food web as a producer, consumer, or decomposer.
You will label each consumer as an herbivore, carnivore, or omnivore.

8. What are we learning?
We are learning about food chains and food webs in ecosystems.
Food chains and food webs show us feeding relationships and, therefore, how energy moves from organism to organism in an ecosystem.
Food chains and food webs show us how all things in an ecosystem and on Earth are dependent upon each other for survival.
They also allow us to predict how a change in one part can affect all of the other parts of an ecosystem.

9. Why are we learning this?
We need to learn about food chains and food webs because we are part of them.
We need to know how we depend upon other organisms for survival and they depend upon us.
We need to know this so we can be more aware of how things that we do can affect our environment.
We need to be more conscious of our activities so we might make better choices when we do things that alter our environment.
Can you give some examples of things you do that affect the environment (negatively or positively)?

10. What is a food chain?
Shows the feeding relationships in an ecosystem.

11. What is a food web? Shows interconnected food chains in an ecosystem.
Is a better representation of the feeding relationships in an ecosystem

12. What about the arrows in a food chain or food web?
The arrows point in the direction of energy flow.
This means that the arrows point to the organism that is DOING THE EATING, since it is the one that is getting the energy.

13. What kinds of organisms are in food chains and food webs?
There are 3 basic kinds of organisms in food chains and food webs.
Producers
Consumers
Decomposers

14. Producers Produce their own food (usually through photosynthesis)
Are at the bottom of a food chain
Includes plants, algae, etc.

15. Consumers Have to eat other organisms
Are in the middle and at the top of the food chain
Includes animals that eat plants or other animals

16. Decomposers
Break down dead organisms and return their nutrients to the environment
Includes fungi (mushrooms, etc.) and bacteria

17. What types of consumers are there?
There are 3 different kinds of consumers:
Herbivores
Carnivores
Omnivores

18. Herbivores
Eat only producers (plant materials)

19. Carnivores
Eat only other animals (meat)

20. Omnivores
Eat both plants and animals

21. Rules for Creating Food Chains and Food Webs
Always begin your food chain/web with a producer.
Always draw the arrows so that they point to the organism that is DOING THE EATING, since this is the direction of energy flow in the feeding relationship.
Assignment:
You will create a food web for the Mono Lake Ecosystem.
You will draw the food web and label each organism in the food web as a producer, consumer, or decomposer.
You will label each consumer as an herbivore, carnivore, or omnivore.

22. Food Chains and Food Webs Involve Us All!!

23. DO NOW MONDAY
Observe both the aquatic and terrestrial ecosystem for your group. Person 3 in each group should fill out the information for your ecosystem only.
DO NOT MOVE THE ECOSYSTEMS from the place where they have been put because we need to observe the natural behaviors of these animals.

24. TODAY’S PLAN TODAY’S DO
To describe the transfer of energy in relationships.
TODAY’S DO
We will review the Mono Lake Food Web you drew on Page 3 of your packet on Friday.
We will discuss energy transfer and the energy pyramid of a food chain/web.
We will create our own energy pyramid for a food web and label it.

25. MONO LAKE FOOD WEB         Halobacteria (Decomposers)
Planktonic
Algae
(Producer)
Brine
Shrimp  
Eared Grebe
Red-necked Phallarope
Wilson’s Phallarope
California Gull 
Coyote   
Caspian Tern
Benthic
Algae
(Producer)
Brine
Flies  
Snowy Plover

26. Energy Transfer in Food Chains and Food Webs
When one organism eats another, energy is transferred from the one who was eaten to the one who did the eating.
For example, when a snake eats a mouse, energy is transferred from the mouse to the snake.

27. Energy Transfer in Food Chains and Food Webs
However, the snake doesn’t get 100% of the mouse’s energy.
Only 10% of the energy from the mouse gets passed on to the snake.
The other 90% of the energy that was in the mouse was used by the mouse to live and/or released as heat from the mouse’s body.

28. Energy Transfer in Food Chains and Food Webs

29. Energy Pyramid Activity

30. Materials 1 pair of scissors Tape 1 roll adding machine tape
1 meter stick
Sharpie

31. Information
For this lab 1mm = 1 kcal (kilocalorie) of energy!
Remember only 10% of energy is passed up through the trophic levels.
10%
10%
10%

32. Step one – Producer Level
Cut a strip of adding machine tape 1,000mm (1m) long.
This represents 1,000kca of energy.
In the middle of the adding machine tape label it “Producers” with the sharpie.
Producers

33. Step two – 1st Level Consumers (Herbivores) Also call Primary Consumers
Only 10% of the energy is passed from the producer level to the primary consumer level. So…..
10% = .1
1,000mm X .1 = 100mm (10cm)
Our 1st Level Consumer strip needs to be 100mm long.
Cut a strip 100mm long and label it “1st Consumers” with the sharpie.
Primary Consumers

34. Step Three – 2nd Level Consumers (Eat 1st Level Consumers) Also called Secondary Consumers
Only 10% of the energy is passed from the primary consumer level to the secondary consumer level. So…..
10% = .1
100mm X .1 = 10mm (1 cm)
Our 2nd Level Consumer strip needs to be 10mm long.
Cut a strip 10mm long and label it “2nd Consumers” with the sharpie.
Consumers S.

35. Step Four – 3rd Level Consumers (Eat 2nd Level Consumers) Also called Tertiary Consumers
Only 10% of the energy is passed from the secondary consumer level to the tertiary consumer level. So…..
10% = .1
10mm X .1 = 1mm
Our Third Level Consumer strip needs to be 1mm long.
Cut a strip 10mm long. You cannot label this. It is too small!

36. Step five – tape it all together
Tape all of this together and attach to a sheet of poster paper!!!!

37. Step Six – Finish Labeling
First title your model “Energy Pyramid”
Next, label your 3rd Level Consumers.

38. Step six Continued – Add Organisms
Use this food web as reference.
Draw the organisms on the appropriate trophic level!

39. DO NOW TUESDAY Create a food web with the following organisms:
grass mouse fox snake
owl grasshopper rabbit

41. TODAY’S PLAN TODAY’S DO Describe limiting factors.
Explain environmental limiting factors that influence the growth of populations.
TODAY’S DO
We will create a class food web and answer questions.
We will discuss limiting factors and carrying capacity.

42. Factors that Affect Population Size in an Ecosystem
There are many factors that affect how large a population can become.
Can you think of any?
Predators
Natural disasters
Availability of food, water, shelter
Disease
Human Activity
Things like these that keep a population from growing out of control are called LIMITING FACTORS.

43. LIMITING FACTORS KEEP A POPULATION AT ITS CARRYING CAPACITY
Carrying capacity is the maximum number of individuals that the resources of an ecosystem can support.
When a population is at its carrying capacity, the birth rate and death rate in the population are about the same so the population remains a stable size.
Limiting Factors keep a population at its carrying capacity.

44. Limiting Factors and Carrying Capacity

45. CARRYING CAPACITY

47. Practice Problem A: Around 65 rabbits
Q: What’s the carrying capacity of this population?
A: Around 65 rabbits
Q: When did this population reach its carrying capacity?
A: Around August 1