In a food web, the arrows represent the flow of energy and nutrients from one organism to another. Specifically, an arrow points from the organism that is being consumed (the prey) to the organism that is doing the consuming (the predator). This directional arrow indicates that the energy from the prey is transferred to the predator when the latter eats the former.
For example, if an arrow goes from a plant to a herbivore, it signifies that the herbivore is gaining energy by feeding on the plant. Similarly, if an arrow points from a herbivore to a carnivore, it shows that the carnivore is obtaining energy by consuming the herbivore. Understanding these connections is crucial for examining the dynamics of ecosystems, as it illustrates how species interact and how energy flows through the environment.