Members of the soil ecosystem must play by the same rules as larger, more familiar creatures. They face the same struggle to eat or be eaten. Space and food are just as valuable.
Some places are better to live than others.
And each species has its own job, or niche, in this huge web of life. Scientists work hard to find and identify soil wildlife. It's even harder to figure out what creatures do down there. The most important soil organisms are very, very tiny. You can't put a radio collar on a bacterium and follow it around.