Wolves of Yellowstone Video Case Study

Wolves of Yellowstone and

the “Trophic Cascade”

A Case Study

What is a Trophic Cascade?

A series of indirect
interactions within a
food web that have the
potential to impact every
organism within the food
web that is below the
predator.

This is to be completed individually. Make sure
you have long printer paper and colored pens/pencils.

Challenge! As the next 2 video clips
are played complete a food web to
accurately describe the trophic
relationships in the Yellowstone region.
This food web will be used to help you
explain the changes in populations that
occurred in response to the reintroduction
of wolves.

Inside Yellowstone-Winter

Wolf Research

Mission #1

Watch the video and listen to the
dialogue and ID every type of
species spoken about or seen in
this clip. Write each specie only
once on your printer paper, make sure it's added to the food web you have been creating.

Mission #2

● Listen for additional species to add to

the food web

● Confirm trophic relationships already

identified in the food crop

● Find new trophic relationships

Wolves of Yellowstone-The

Hunt

Mission #3

Identify an example of interconnectedness
of an ecosystem by connecting:

● Elk and Salmon–Connect with a dottedpink

line

● Wolves and Eagles–Connect with a dotted

blue line

● Wolves and Songbirds–Connect with a dotted

green line

Mission #4

Identify 2 of each of the following and label with appropriate
acronym.

●Producer–P

●Heterotroph–HT

●Herbivore–H

●Carnivore–C

●Primary Consumer–PC

●Secondary Consumer–SC

●Tertiary Consumer–TC

●Scavenger–S

●Detrivore–DT

●Decomposer–DC

On the back of your food web poster, complete the last
Mission

Answer the following questions:

❖

How should humans be placed in your food web?

❖

In terms of boundaries, how certain can we be that the regeneration of the
Yellowstone River Basin is a result of the re-introduction of the wolves?

❖

How is this Case Study a “response to a disturbance”?

❖

If a disease were to wipe out the elks, how resilient would the ecosystem be?
Why is it different than when the wolves (apex predator) were eliminated?