Cougars and Trees in a Trophic Cascade

• In this activity, students analyze and interpret two graphs from a study that investigated the ecosystem effects of the displacement of cougars in a national park.
• Students are tasked with describing how changes in one population in an ecosystem can affect other populations through a trophic cascade. 

Positives

• This resource is an excellent introduction to reading scientific papers and allows students to practice simplifying complex ideas and information.
• The resource is available in Spanish and English, and includes educator materials, a student handout, and the original research paper.

Additional Prerequisites

• Edits to the Google documents can be made by making a copy.
• Students should have a strong understanding of reading and interpreting graphs and a general understanding of trophic levels and how they interact.
• Once printed out, this resource does not require access to the internet.
• There are specific standards listed for AP Biology, AP Environmental Science and IB courses that you can reference.
  

Differentiation

• In more advanced classes, students can read the full research paper provided in the resource and analyze the methods, data analysis, and conclusions.
• The educator materials include a guide for using the resource, background information, an explanation of how to interpret the graph, discussion questions, and a list of key terms, which can be used to assist students with less science or math backgrounds.
  
• This lesson can also be used in math and statistics classes during lessons about standard error, correlation coefficients, and sampling and in social studies classes during lessons about the environmental impact of the tourism industry.
• Similar resources include this video on trophic pyramids and this video on how trophic levels interact.