So you’ve got the origin of your universe (or perhaps you used our universe as a template, which does save a lot of effort). So now that you know how it all began, it’s time to move things to the next level. Namely, what’s going on in the places your characters will be living, working, loving, dying, and in other ways advancing the plot.
Cosmology is decided. Time to move to Ecology
Now when I talk Ecology, that’s a word with a lot of meanings and a lot of applications. So for the sake of the column I’m defining Ecology in world building as how you define how the living parts of your setting (world, worlds, etc.) work, relate, interact, etc. Your plants, animals, biospheres, diseases, and the like. I’ll refer to it as Ecology with a capital “E” for general purposes, and with a small “e” for specifics.
You know, where life comes from and/or lives. Life in short, like your characters, or the things they’ll be interacting with, domesticating, fighting, eating, and so on. Or come to think of it the reverse as well . . .