The feeding relationships among species are known as trophic relationships. In a food chain, energy and nutrients are transferred from one organism to another as they are consumed by predators. For example, a grasshopper eats grass and is in turn eaten by a frog, which is then consumed by a bird. The grasshopper is known as the "primary producer," while the frog and bird are known as "secondary consumers." The presence of certain species can benefit others in the ecosystem by providing food or habitat. For example, trees provide habitat and food for many species, including birds, squirrels, and insects.
