The Chesapeake Bay is the largest estuary in the United States. Explore its origins, organisms, and contributing rivers with this PowerPoint. It opens with several slides of general information on the formation of estuaries, then it...

Explore structures within the realm of gas exchange in terrestrial and aquatic life.  The excellent, labelled diagrams and clear descriptions help your students view the different structures and adaptations that have...

The need for a respiratory system in humans versus being reliant on gas exchange structures is demonstrated. There are many details about the advantages and disadvantages of each mechanism.  Students are able to learn about the...