The various sorts of trophs

[lpetrich]

-troph designates an organism that does one of these things
-trophic is an associated adjective
-trophy is the associated noun
An autotroph has autotrophic metabolism, and does autotrophy, for instance.

In order of combination:

• Energy source:
  •  Phototroph - light
  •  Chemotroph - chemical reactions
• Raw materials (hydrogen/electron sources):
  •  Lithotroph - inorganic molecules
  •  Organotroph - organic molecules, usually biological ones
• Source of biological molecules
  •  Autotroph - manufacture by the organism
  •  Heterotroph - already-existing ones

The most familiar sorts of metabolism are

• Photo-litho-autotroph -- plants
• Chemo-organo-heterotroph -- animals, fungi, and decay organisms

That does not exhaust the possible combinations, and some others are known in some organisms.

• Photo-organo-heterotroph -- organisms that get their energy from light but need biological molecules from outside. Like haloarchaea
• Chemo-litho-heterotroph -- organisms that get their energy from inorganic-chemical reactions but need biological molecules from outside
• Chemo-litho-autotroph -- organisms that get their energy from inorganic-chemical reactions and make their own biological molecules. Like methanogens and inorganic-compound oxidizers
• Chemo-organo-autotroph - like the above but getting energy from organic-chemical reactions

There are variations like  Auxotrophy - almost autotrophy but needing some biological molecule, like some vitamin. Some forms of heterotrophy are very close to autotrophy, like some bacteria and fungi being able to use any of a variety of biological molecules as its sole carbon source.

Some organisms can switch between different energy and raw-material sources depending on what is convenient or available:  Mixotroph

Here are some additional energy sources that some organisms have been known to use:
 Radiotrophic fungus - some melanin-containing fungi can get energy from ionizing radiation.
 Electrotroph - an organism that can get energy from electric currents.
However, I could find no organisms that get their energy from mechanotrophy, by extracting mechanical energy. I also had no success for thermotrophy, extracting energy from heat flows.

 

[untermensche]

In life there is the purposeful use of energy.

The need to acquire energy.

So you can need to acquire more energy.

Seems pointless.