Educational Media Reviews Online

Branches on the Tree of Life, a ten-part series from BioMEDIA Associates, is now halfway complete with the addition of the three DVDs reviewed here: Molluscs, Annelids and Arthropods. The series aims to provide an introduction to the evolution, anatomy, behavior and habitat of organisms typically covered in biology curricula. Other titles in the series released as of 2007 include Echinoderms, Chordates and Sponges, among others. When the series transitioned from VHS format to DVD, digital image banks and study guides were added; study guides and program descriptions also are available online from the BioMEDIA Associates website.

Each of the DVDs reviewed here is an engaging and classroom-ready production no more than twenty-five minutes in length. The content of each DVD is divided into chapters for easy navigation, and each chapter is short enough that it can be screened in its entirety even if only a few of its topics—for example, defense mechanisms but not fossil findings—will be picked up in a lecture.

All three programs are brief and introductory in scope. Molluscs describes the Phylum Mollusca as a whole and then investigates four well-known classes within the phylum: chitons, gastropods, bivalves and cephalopods. Annelids features the Phylum Annelida and the classes polychaeta, oligochaeta, and hirudinea. Arthropods features the Phylum Arthropoda, with detailed treatment of crustaceans, chelicerates, and uniramians. Topics include and evolutionary relationships, life functions, and ecological interactions.

The narrator of the films varies his pace to maintain the viewer's interest and to place emphasis on significant or surprising facts. Thought-provoking nuggets of detail are sprinkled into high-level overviews: for example, in a piece on annelid habitats we learn that a worm's segmented anatomy helps it burrow into the ground. The tone of the narration is polished, yet there are interludes of humor. For example, when we're told that mud can be a difficult living environment "because of the way it compresses," we're shown scientists falling over themselves as they try to pull their feet out of the sticky stuff.

The photography in these DVDs is captivating. Images of microscopic organisms are crystal clear and underwater colors are stunning. Some of the outdoor footage is lackluster, but this doesn't detract much from the overall experience. Scientific terms are usually defined with lively and descriptive language (worms in marine habitats use "feathery filters" to capture floating bits of food), but students new to biology might appreciate more on-screen text. For example, we're shown how a worm uses its "setae" to keep from being pulled from the ground, but who could guess the spelling of that word?

These DVDs are interesting, engaging, educational and professionally produced. They are highly recommended for high school and junior high school collections. The content may be too basic for mainstream college use but the tone is academic enough that if undergrads want a review of high school biology, these DVDs won't seem out of place in an academic library collection.