Some Animals Are More Equal than Others: Keystone Species and Trophic Cascades


Keystone species and trophic cascades are fundamental concepts in ecology. This short film tells the story of how these concepts were first established through the pioneering experiments of two young researchers: Robert Paine and James Estes.

Short Films:
(Duration: 19 min 29 sec)
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Tips From Teachers

“Just as I began to review for the IB exams, HHMI Biointeractive published this short film. After watching it, my students were able to make connections between bottom-up and top-down regulation of ecosystems, and learn how trophic cascades occur. I love how a film can help me explain concepts to students; and I love how a film can stimulate ideas that allow me to engage with my students so they, too, can start to see patterns in nature. ” -- Ryan Reardon, Jefferson County International Baccalaureate, AL

Curriculum Connections:

NGSS (2013) LS
LS2.A, LS2.B, LS2.C, LS4.C
AP Biology (2015)
4.A.5, 4.A.6, 4.B.3, 4.C.4
AP Environmental Science (2013)
IB Biology (2016)
4.1, 4.2, C.1, C.2, C.3, C.4, C.5
IB Environmental Systems and Societies (2017)
2.2, 2.3, 2.4, 3.3
Common Core (2010)
ELA.RST.9-12.2, WHST.9-12.4
Vision and Change (2009)
CC4, CC5