Bioluminescence

Bioluminescence is a way of living organisms to emit light. It is employed by nearly all Pandoran animals. Even the Na'vi have patterns of glowing dots that are unique to each individual. To avoid being detected by predators or pray, animals can damp down their own light. The RDA exploited it as another resource in the form of exotic jewelry and clothing.

Complete darkness is rare on Pandora. The large moon orbits a gas giant planet that in turn orbits a star with a stellar companion. Because of this unusual arrangement, most of Pandora's nights have some illumination; fully dark nights are few and far between. Thus, there was little evolutionary pressure on Pandoran fauna to develop night vision, echolocation, infrared sensors, or other methods of "seeing" in low-light conditions.

Some scientists theorize that nature found another way for Pandoran life forms to locate and identify one another. Bioluminescence, the production of "cold light" by living organisms, is employed by  almost all Pandoran animals and plants to display their shape and location in the absence of external illumination. Even the Na'vi have patterns of glowing dots, which, like fingerprints, are unique to each individual. Anemonoid line the dense forest floors and waterways, providing the most light in the night landscape.

Bioluminescent plants

Most of Pandora's flora and fauna emits only one single color, often green, blue, indigo, or violet. There are exceptions like the Warbonnet Fern. Its leaves are illuminated by a broad band of red near their stems and by an iridescent blue near their tips. On Pandora, there is also a bioluminescent moss that is touch-sensitive. It will send out rings of blue-green light as a reaction to footsteps.

Bioluminescence is an enzymatic reaction that produces so called cold light. This reaction raises the valence electrons in the molecules of an organic compound to an orbit of higher energy. While decaying to its original state the electrons emit photons of visible light. It is a highly efficient reaction as it converts nearly all energy into light.

The reaction can occur within the metabolism of the creature or within symbiotic organisms that live inside of specialized organs, receiving food and oxygen from their host, and producing light in return.

There are several ways in which light production can be controlled:

    * Limiting the availability of the involved chemicals
    * The reaction takes place in an organ that can be moved away from the surface
    * A translucent muscle carries the light from an internal organ to the surface by expansion and contraction
    * Covering of the light producing area with dark pigment cells (melanophores)
A dark membrane that can be drawn over the light producing area

Flora of Pandora

 

Plant life on Pandora is strange and even fantastic. Yet some plants on Pandora bear a striking resemblance to plants on Earth. The diversity of plant life and its range and its size and complexity suggest that, as on Earth, the environment on Pandora acts as a strong force for natural selection. The environmental factors that plants experience on Earth - radiation, water, atmospheric gases, and gravity - are present on Pandora, as well, although their characteristics differ profoundly, as the resulting plant life shows. The atmosphere on Pandora is thicker than on Earth, with higher concentration of carbon dioxide as well as elevated levels of hydrogen sulfide and xenon. Gravity is weaker, while the satellite's magnetic field is incredibly strong. All of these factors have determined the evolution of plant life on Pandora.

As on Earth, plants on Pandora have evolved the ability to respond to gravity, though its force is weaker on Pandora. As a result, gigantism is found in plants, and the typical orientation - stems growing up and roots growing down - does not necessarily hold true. The tallest trees, which are limited on Earth by the physical height to which their transport tissue can move water, reach much greater heights on Pandora in its lower gravity. The presence of a magnetic field and ionizing radiation have selected for growth responses toward these stimuli, named magnetotropism, which is found on both Earth and Pandora, seem quite tame by comparison.

Although, plants on Pandora have been given various common and Latin names, using the standard nomenclature accepted on Earth for biological organisms, their systematic classification remains a mystery. Some appear quite simple and perhaps primitive, while others have fantastic, seemingly highly evolved adaptations to the particular conditions on Pandora.

Most intriguing is the presence of life-forms that have characteristics of both plants and animals. These zooplantae (or colloquially "planimals") have incipient nervous systems that give them the kind of organic intelligence found in primitive animals. This discovery continues to baffle and delight biologists and botanists who mus reassess their preconceptions about the mechanics of life. As most everything here, this mystery awaits furth study by scientists lucky enough to make it to Pandora.

More after the Jump...