Understanding ecosystems  [videorecording] / 
Educational Video Network ; author, Mary Lee Nolan. 
 - Huntsville, Tex. :  Distributed by Educational Video Network,  c1994. 
 - 1 videodisc :  sd., col. ;  4 3/4 in. 
<br/><br/>Videography, Sydney & Mary Lee Nolan; editor, Ryck Berube; narrator, Thomas F. Soare; executive producer, George H. Russell.  Videography, Sydney & Mary Lee Nolan; editor, Ryck Berube; narrator, Thomas F. Soare; executive producer, George H. Russell. 
<br/><br/> Ecosystems can range in size from tidal pools to the entire planet. Understanding the boundaries of various collections of organisms is the first step toward maintaining the balance to preserve them. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Biotic communities.<br/>Ecology--Videocassettes.<br/>Science films.