San Francisco Bay has the designation of being the most heavily invaded estuary in the world.
View this segment to learn

• how the Transcontinental Railroad had an effect on the ecology of the Bay.
• ways in which exotic species enter the Bay.
• the prevalence of exotic species in the Bay.
• how often a new species arrives in the Bay.

Download the Viewing Guide for pre- and post-viewing discussion questions, activities, and additional resources to use with students.

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