| ESSENTIAL ITEM | Source | Brock's Terms | Lynch and Poole |
|---|---|---|---|
| Carbon from: | Organics | Heterotroph | Heterotroph |
| CO2 | Autotroph | Autotroph | |
| Energy from: | Light | Phototroph | Phototroph |
| Chemicals | Chemotroph | Chemotroph | |
| Electrons from: | Organics | Brock doesn't mention | Organotroph |
| Inorganics | Lithotroph |
The term heterotroph most often refers to an organism that obtains carbon, energy, and electrons all from organic compounds.