| Gammaproteobacteria | EUBACTERIA>PROTEOBACTERIAE>GAMMAPROTEOBACTERIA |
| Gastrotricha | EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>BILATERIA>PROTOSTOMATA>PLATYZOA>GASTROTRICHA |
| Ginkgoophyta | EUKARYA>ARCHAEPLASTIDA>VIRIDIPLANTAE>STREPTOBIONTA>EMBRYOPHYTA>TRACHEOPHYTA>SPERMOPHYTA>GINKGOOPHYTA |
| Glaucophyta | EUKARYA>ARCHAEPLASTIDA>RHODOPLANTAE>GLAUCOPHYTA |
| Glomeromycota | EUKARYA>OPISTHOKONTA>UNIKONTA>FUNGI>BASAL FUNGI>GLOMEROMYCOTA |
| Gnathifera | see Spiralia |
| Gnathostomata | see Vertebrata |
| Gnathostomulida | EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>BILATERIA>PROTOSTOMATA>SPIRALIA>PLATYZOA>GNATHIFERA>GNATHOSTOMULIDA |
| Gnetophyta | EUKARYA>ARCHAEPLASTIDA>VIRIDIPLANTAE>STREPTOBIONTA>EMBRYOPHYTA>TRACHEOPHYTA>SPERMOPHYTA>GNETOPHYTA |
| Green Algae | EUKARYA>ARCHAEPLASTIDA>VIRIDIPLANTAE>GREEN ALGAE |
| Gymnosperms | EUKARYA>ARCHAEPLASTIDA>VIRIDIPLANTAE>STREPTOBIONTA>EMBRYOPHYTA>TRACHEOPHYTA>SPERMOPHYTA |