EOL has the ability to filter its content by a classification (or hierarchy). This allows you to change the list of taxa shown in the classification browser on the right side of a species page and, optionally, create a filter for EOL based on this classification.

For instance, if you choose a classification containing only marine taxa and select the filtering option, then your view of EOL will only show those taxa and images recognized by the marine classification - an Encyclopedia of Marine Life! You can still search for any taxa using the search page.