Once you have added terms to a biological classification, new content will be automatically tagged to the classification by default. This is called autotagging. The system will look for the presence of terms in the text and if it finds a term it will add a link to this term to the node. Autotagging can be problematic because if names of other taxa are mentioned in the text, for example while comparing characters, then these will be tagged, too. For some content types like taxon descriptions or images, this can be undesirable. The other problem is that species names will automatically be tagged to the genus name as well as the species name because both are part of the name. But for example a species description should only be linked to the respective species.
Disable autotagging for a certain content type
Click on Structure in the Admin menu and click on Content types.
Click on the edit link for the content type, e.g. for taxon description.
Click on the vertical Tag options tab near the bottom.
Unselect (Control+Click on PC) all classifications/vocabularies in the 'Vocabularies' box close to the bottom of the page. Save.