Early Animal Life Forms

Loki: Chapter 6

With all the sulfur and the sulfur compounds the chemosynthesizers were producing, it was only natural and expected that animals would evolve to use them. These animals remain today. They take the sulfur and sulfurous acids, combine them with carbohydrates, and use exotic enzymes to produce carbon dioxide and hydrogen sulfide. These are then used to create hydrocarbons and oxygen, with the hydrogen sulfide returning to the ocean at large. Evolutionarily these animals obviously must be more recent than the chemosynthesizers, but today, there are very few chemosynthesizers any distance from one of these C-S transformers (as they were quickly dubbed by a lucky biologist who first recognized their unique properties). No other planet yet encountered uses this interesting method of conserving atoms and energy. Yet it appears work, so well that in fact they are the second most prevalent phylum on the planet.

Most of these C-S transformers are sessile, plant-like, although they would be closer to Earth fungi than plants. The structure consists not of valuable carbohydrates, but of a chitin-like substance that contains a goodly percentage of sulfur. These transformers have adapted so marvelously that there are very few of the IR plants or the chemosynthetic colonies that don't have quite a few of these transformers.

The planet also possesses an incredible amount of life that depends upon the deposition of minerals to survive. Given the number of sulfur depositors, it comes as little surprise that some of these use the deposits to protect themselves. They build a tube out of the sulfur, which helps to anchor the chemosynthesizers near their favorite heat vents. These deposits also attract omnivores that process the sulfur into oxygen. This leads to animals hunting over extinct volcanic beds, digging up sulfur tubes. Interestingly enough, this is one of the few life forms seen away from the heat vents and volcanoes.

With these many paths that evolution took on this world, the flora is quite diverse. However, the animal life on the planet appears to be stunted. There is relatively little mobile animal life, as compared to a world such as Earth. The life consists entirely of sea life, although there is possible evidence of sporadic animal life on the surface.

There are many sessile animals around the volcanoes. These stationary animals feed by filtering out lots of the microscopic plankton analogue. This plankton consists of microscopic sulfur bacteria and a number of small crustaceans and medusa-like omnivores who eat them. The plankton is the main link of the food chain on this planet. The plankton survives by riding in the hot water above the volcanoes, trying to stay out of reach of the other predators. It is only the plankton that is swept out of the volcanic heat that get eaten.

The sessile animals are often also sulfur transformers as well. They will occasionally collect under a large stand of algae, and survive on dead plants and the sulfur extruded by the chitinous transformers. Most of these animals are very similar, however, to the sponge of Earth, save that their skeleton is much richer in sulfur, as a consequence of the immense volcanic activity.

The primary mobile animals in the sea appear to be divided into two phyla. There are the animals which are quite similar to arthropods on Earth, with complete exoskeletons of a material similar to the material used by the fungi-like organisms, a chitin-like substance with additional sulfur atoms, which acts as strong as regular chitin, but is not affected by the eccentric ocean chemistry. There are also animals with internal shells and skeletons. These are divided into the notochordates and the vertebrates. The vertebrates have a similar backbone structure to Earth fish. The notochordates have a smaller nerve channel surrounded by cartilage and a chitinous substance.

The arthropods are nearly as varied on this planet as on Earth. For every niche in the ecosystem, there are arthropods. Some microscopic arthropods live almost directly over the volcanic vents, consuming whatever algae or chemosynthetic bacteria are around. Many more act as carriers, moving back and forth between vents, acting almost as if they were spreading or pollinating the algae. The largest of the arthropods are nearly 1.6 meters long, and weigh nearly fifty kilograms. These arthropods are adapted as carnivores, using huge pincers to grasp smaller animals and slice them up for eating. Many smaller arthropods are herbivorous, eating edges off of the large plants that surround most vents.

The vertebrates on the planet are nearly identical to the fish of early Earth. The fish seem to have branched off very early from the notochordates, who in turn branched off even earlier from the arthropods. The fish on the planet today are for the most part very small and quick, surviving in a niche similar to the niche of birds in a forest. The fish concentrate on speed, and survive by nipping out and eating quickly, and then darting back into the algal growth. None are believed to be transformers or chemosynthetically oriented. Fish are not common at all between vents.

The notochordates are the most interesting of the lot. They are more diverse than the fish. They are also more numerous than the larger arthropods. There are a number of smaller notochordates, which appear to fit into the niches of small fish, or of medusa. In fact, some of the first life observed on the planet were pseudo-medusae. The discovery of the notochord in these medusae was quite shocking, as most biologists had theorized that evolution would not produce notochords until much later in the evolutionary cycle. However, the notochordates appear to be the most advanced branch of animal life on the planet. They have evolved sleep mechanisms that allow travel between vents. In fact, one species of the notochordates appears to be sentient. They use rocks as tools, and have also been seen using living coral as shelter and algae for weaving.

Chris Jones
Sat Feb 18 00:31:33 MST 1995