Highways Block Bighorn Sheep
This Science Bulletin, Highways Block Bighorn Sheep, is based on the scientific research of Clinton Epps. He was interested in understanding if highways built to connect Los Angeles and Las Vegas might affect bighorn sheep populations.
As the human population gets more connected, animal populations become more separated.
Recently, biologists studied 27 groups of desert bighorn sheep, which live on the rocky mountains of the Mojave and Sonoran deserts. The scientists found that sheep populations nearest highways and cities were the most genetically inbred.
The study confirms what scientists have long suspected—that bighorns cannot cross major fenced highways and other urban barriers to join new groups. Without adequate gene flow, the health—and existence—of the bighorn sheep are at risk.
Questions for Thought
Ask students to write any questions they have about the Science Bulletin, while they are watching it. Collect these questions and after class, write the questions on a piece of chart paper that can easily be seen during the course of the unit.
Note: Refer back to these questions throughout the unit and check off questions that have been answered along the way.
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SubtopicHuman Impacts, Populations