Organic creatures on the MUX are generally not robots or Transformers. Their fleshy cores are considered more fragile and weak than inorganic characters, and therefore deal less damage and receive more damage in combat. However, certain advanced technology can overcome these limitations -- for example, Nebulans are technically organic in a physical sense, but their higher-tech weapons and armor give them an edge in fighting, so they are not set "organic" according to the combat code.
History
Organic life is generally cherished and protected by Optimus Prime, while looked down at with scorn by Megatron.