Name: ______Date: ______Period ______

PRACTICE WITH FOOD WEBS

Procedure:

1.  Use scissors to cut the pictures apart.

2.  Sort the pictures into groups according to their energy sources: Producers, Primary Consumers (herbivores), Secondary Consumers (1st level of carnivores/omnivores), Tertiary Consumers (2nd level of carnivores/omnivores)

PART I QUESTIONS:

A.  What is the main source of energy for the organisms you are grouping? ______

B.  List all of the producers (7): ______

______

C.  List all of the organisms that are only primary consumers (7): ______

______

D.  List all of the Secondary Consumers (5): ______

______

E.  List all of the Tertiary Consumers (5): ______

______

3.  Use the same pictures to form a food web that would occur in Yellowstone. Use arrows to show the flow of energy. Remember a food web is several food chains linked together. Once completed have your teacher

SIGN HERE ______.

PART II QUESTIONS

A.  Where is most energy located in a pyramid, food chain, or food web? ______

B.  As you move up the food web, what happens to the amount of energy? ______

Number of organisms? ______

Amount of Biomass? ______

C.  How much energy is passed on to each trophic level? ______

a. What happens to the rest of the energy that is not passed on? ______

b.  Knowing this and using the ocean food chain below, which organism represents the trophic level containing approximately 1% of the initial amount of solar energy acquired by the phytoplankton?______

D.  What is your food web missing that would be needed in ecosystems to help recycle the nutrients when these organisms die? ______

E.  Would there be more predators or prey in a particular community? Explain.

PART III PROCEDURE:

1.  Flip over the wolves square in your food web to simulate that it has become extinct. By doing this how does it directly change the Ecosystem, think about . . . . .

  1. What organisms would increase in number? ______
  2. AND because the organisms that increased in number you answered above, their food sources would probably decrease & the organisms that eat the same food sources as them and compete for these limited resources would probably decrease. Flip over all of the organisms that would be affected by this change to simulate them dying during competition or depletion of resources. List organisms that would probably decrease over time: ______

______

2.  The scenario listed above did actually occur in Yellowstone National Park. Wolves were extinct for over 70 years in that area which dramatically changed the ecosystem. Watch the following video over this change: https://www.youtube.com/watch?v=ysa5OBhXz-Q

Below explain what happened to the ecosystem when wolves were introduced back into Yellowstone:

3.  Describe how humans might change (or are currently changing) food webs and ecosystems.

4.  Why can’t food chains go on forever? (8th order, 9th order, & 10th order consumers).