How do these animals/plants live in the biome Grassland?

Well my only guess would be the food web and the trophic levels. Which ones are plant eaters? Which ones are carnivores? Plant eater animals eat the plants, animals higher in the trophic level eat the plant eater animals. And on and on. Also, Clover and sunflowers are edible, so plant eaters eat the seeds, spread thema round in the grassland through poop. Etc... For plants like the gooldenrod with light seeds that get picked up in the wind, there arent any obstacles to stop them from flying everywhere and germinating far away in the grassland. I could go on and on :P