This resource is exclusively for zoology:
These resources are exclusively for botany:
Both of these databases are good places to start searching, especially if you only need a few good articles:
These databases provide more complete coverage of biological journals. Additional resources exclusive to botany and zoology are listed in the side column.
"The power of citation searching lies in the capacity to take a seminal article and uncover who the author was influenced by (who was cited) and go forward in time to discover how that seminal research affected newer works (who is citing it)."*
Use the Citation Searching tab on this page to see how it works.
*Tenopir, C. (January 01, 2001). INFOTECH - Online Databases - The Power of Citation Searching. Library Journal, 126, 18, 39.