These sources will help you familiarize yourself with new terms and concepts you come across in your reading.
Dictionaries
A dictionary of biology,
Electronic Book and Armstrong Reference
A dictionary of ecology, Electronic Book
Grzimek's animal life encyclopedia, Armstrong Reference
A dictionary of biology,
Electronic Book and
Armstrong Reference
A dictionary of ecology, Electronic BookGrzimek's animal life encyclopedia,
Armstrong Reference Henderson's dictionary of biological terms, Armstrong Reference and Armstrong Stacks
Encyclopedias
AccessScience (McGraw-Hill Encyclopedia of Science & Technology Online): Provides authoritative information for non-specialists on a wide variety of science-related topics. Includes the 20-volume McGraw-Hill Encyclopedia of Science & Technology, the McGraw-Hill Dictionary of Scientific & Technical Terms and the Yearbooks of Science & Technology in addition to biographies from the Hutchinson Dictionary of Scientific Biography, selected Science News articles, and links to evaluated web sites.
Wikipedia: A free online encyclopedia that anyone can edit. May provide useful information in a preliminary search, including references to sources for further research.