Let there be Life

Okay, so we have a planet now, and have some idea of the physical nature of said planet. Now we need life, otherwise, why are we creating this world? Even if all the life is dead when the story occurs, life did by necessity happen. So, life can be divided into several groups, some of which we don't need to spend much time on.

Bacteria come first, always. There are more species of bacteria on earth than anything else. Seriously. If you totaled the numbers of species of all the other kingdoms, that total would not equal the bacteria. The bacteria form the foundation for evolution. They fix the elements in forms higher organisms use. They aid higher organisms in digestion, metabolism, vitamin formation, and that's just here on earth.

But bacteria don't usually play a role in fiction except as pathogens, so let's just assume a fully varied and rich bacterial ecosystem upon our planet and move on.

Plants. Or, if you prefer, autotrophs. This level of life is differentiated from the rest by its food source. The autotrophs do not get their energy from other organisms. They take direct energy, such as from the sun or thermal vents, and by some process convert that energy into the fuel necessary for metabolism. On this planet, that equals algae, grasses, bushes, trees, all of which convert sunlight into sugar via photosynthesis.

Consider your physical world as you develop the "green background." Remember that it doesn't have to just be a background. Plants are vigorous organisms that do respond to the world around them even if we humans don't notice.

You can have real fun with plants. There is no limit to the complexity of the plant-life other than your imagination. But, try to remember, that which evolves does so for a reason. What niche does the plant fill? How did feature X come to be? As in, what goal does it achieve for the plant which evolved it?

The point to this world building game is to develop something that seems potentially real. If an organism has developed a strange ability, feature, appearance, or whatever, there should be a rationale behind it other than, "I need this for scene 48 of my story." Whether or not you explain the rationale in the story, having one adds depth to the world.

Next group, the heterotrophs. Heterotrophs get the energy for cellular metabolism by consuming other organisms. They can do this passively, like mold on bread, or actively, like a cow eating grass or a man eating a steak. Generally, for the purposes of fictional world building, we're probably going to go straight to the active eaters, unless the fungi and whatnot are important to your story. (It probably wouldn't hurt to develop one or two molds, either for decomposition or for medicine. Penicillin started as bread mold, after all)

Active eaters come in three varieties. Three, you say, not two? That's right, three. Herbivores, carnivores, and omnivores.

Herbivores are the pure prey animals. They eat plants. Cattle, deer, horses. All herbivores. Now, what sort of creature would be able to eat your plants? Do your plants have defenses against being eaten? How do the herbivores overcome these defenses?

Questions of herbivores tie in directly to the next group, the pure carnivores. Carnivores eat herbivores, of course, but. but. but. Herbivores don't like to be eaten. They run, like horses and gazelle, or stand and fight, like buffalo and elephants. The predator is supremely adapted to overcoming the herbivore. Cheetahs run down gazelle. Lions and wolves use cooperative hunting to bring down their tough opponents.

So when you develop herbivores, you also develop their predators. Most of a herbivore's physical abilities are going to be tied to the abilities of the creature which eats it.

The third group is the omnivore. Humans are omnivores: we eat anything. Plant, animal, chemical, we eat it all. Bears are also considered omnivorous, as are some species of primates. So, since we're writing fantasy for other humans to read (you are human, right?) it's probably highly likely that your planet will have humanoids. It's even possible that these humanoids will be indistinguishable from those living here on earth. And that's okay, since this is fantasy.

Next time: how much depth does a fantasy world really need?