Operational definition
Classification axis.
The classification of an organism according to the proximate source that supplies the energetic drive for biological energy conservation.
The primary categories are:
- phototroph — light provides the energetic drive;
- chemotroph — exergonic chemical reactions provide the energetic drive;
- photo-chemo flexible organism — the relative contribution of the two changes with conditions.
This axis does not identify the organism’s carbon source or electron donor.
11.1 Phototroph
Light supplies the primary energetic drive.
11.2 Chemotroph
Chemical transformations supply the primary energetic drive.
11.3 Photo-chemo flexible
The organism can change the relative contribution of phototrophy and chemotrophy.