BIOLUMININESCENCE

Bioluminescence is the production and emission of light by a living organism. Bioluminescence is a naturally occurring form of chemiluminescence where energy is released by a chemical reaction in the form of light emission. Fireflies, anglerfish, and other creatures produce the chemicals luciferin (a pigment) and luciferase (an enzyme). The luceferin reacts with oxygen to create light. The luciferase acts as a catalyst to speed up the reaction, which is sometimes mediated by cofactors such as calcium ions or ATP. The chemical reaction can occur either inside or outside the cell. In bacteria, the expression of genes related to bioluminescence is controlled by an operon called the Lux operon. Based on its diversity and phylogenetic distribution, it is estimated that bioluminescence has arisen independently as many as 30 times in the course of evolution

Bioluminescence in Biotechnology
Bioluminescent organisms are a target for many areas of research. Luciferase systems are widely used in the field of genetic engineering as reporter genes. Luciferase systems have also been harnessed for biomedical research using bioluminescence imaging.Vibrio symbiosis with numerous marine invertebrates and fish, namely the Hawaiian Bobtail Squid (Euprymna scolopes), are key experimental model for symbiosis, quorum sensing, and bioluminescence.The structure of photophores, the light producing organs in bioluminescent organisms, are being investigated by industrial designers.
All cells produce some form of bioluminescence within the electromagnetic spectrum, but most are neither visible nor noticeable to the naked eye. Every organism's bioluminescence is unique in wavelength, duration, timing and regularity of flashes.

Application
Glowing trees to line highways to save government electricity bills
Christmas trees that do not need lights, reducing danger from electrical fires
Agricultural crops and domestic plants that luminesce when they need watering New methods for detecting bacterial contamination of meats and other foods
Bio-identifiers for escaped convicts and mental patients

Detecting bacterial species in suspicious corpses

Novelty pets that bioluminesce (rabbits, mice, fish etc.)

example : every living organism on Pandora is bioluminescent.