Every grade-schooler knows quite clearly that big, scary carnivorous animals eat the smaller, weaker animals, who in turn eat other smaller things, who in turn eat even tinier animals, who in turn eat microscopic animals, who, given the right conditions, can turn around and eat, well, about anything they damn well please, including the bigger prey. Those bacteria are crafty buggers after all.

Like most of us, filmmaker Karen Meyer always knew that biological predators like wolves, lions, and grizzly bears impacted the populations of the other animals they preyed on, things like rabbits, gazelles, or trout. But she never understood exactly how the predator-prey relationship could affect an entire ecosystem.

“The ecosystems and the natural world isn’t as simple as we sometimes think that it is,” Meyer says. “It’s a far more complex world, and as Aldo Leopold said, when you take one thing out, you’re affecting everything.”

Karen and Ralf Meyer, her partner at Green Fire Productions, were initially introduced to this new field of study examining the role that predators play in an ecosystem by an article in National Geographic. But they soon learned that most of the information on the subject was only being published in scientific journals.

“Those journals are hard to read,” Meyer says. “They’re not made for the general public, and the information was just not getting out there.”

So the duo started to meet with scientists and traveled to Yellowstone National Park and wilderness areas in the West. She realized that not only do predators help maintain the vitality of their ecosystems, but without them, their habitats suffer. The Meyers turned their discoveries into the documentary Lords of Nature: Life in a Land of Great Predators.

“Film is a powerful medium and one that most of us really enjoy, and so this is a great way to bring these issues of what role the top predators play in our ecosystem right there, front and center, for people in the audience,” Meyer says.

Lords of Nature highlights the ideas of Aldo Leopold, a wildlife ecologist who, 70 years ago, warned what would happen if an ecosystem lost its top predators. One major topic the Meyers wanted to cover was the interaction between ranchers in Minnesota and wolves. The ranchers are currently dealing with the largest wolf population in the continental United States, but they are adapting to the situation.

“Despite all of the fears that we’ve been ingrained with about having wolves around, [ranchers have] been able to overcome them,” Meyer says. “And with just a few changes to the way that they raise their livestock, they’ve been able to reduce the impact of wolves on their animals.” How we choose to deal with predators is something of a moral decision. After all, human beings can change the way they do things in order to coexist with wildlife.

And because these ranchers found a way to adapt, Meyers believes they not only show the rest of us how it can be done, but their actions also say something about the human spirit.

“We have a lot of ability to make changes even though we sometimes think that we don’t,” she says.

Lords of Nature has been shown all over the world, from Chicago to South Africa. “I’ve heard over and over since the film was released that it’s a very powerful film that engages people on many levels,” Meyer says. “You’ll come away with an entirely new understanding of wildlife and their role in our world.