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...