Final answer:
A food web is a complex diagram that represents the multiple interacting pathways through which energy flows within an ecosystem, showing the interconnected feeding relationships between organisms.
Step-by-step explanation:
The diagram that shows how energy moves through an ecosystem is known as a food web. Unlike a food chain, which illustrates a single pathway of energy flow, a food web provides a more complex representation involving multiple interacting pathways through which energy flows and matter cycles within an ecosystem. This ecological model includes multiple intersecting food chains, demonstrating that an organism typically partakes in several feeding relationships - both as predator and prey. Food webs are a more realistic depiction of the trophic interactions within ecosystems because they illustrate the interconnectedness and the intricate nature of food chains.
Food-web diagrams help us understand how energy flows directionally through an ecosystem, from photosynthetic organisms, such as plants and algae, to herbivores, and then to various levels of carnivores. They also reveal the dynamics of ecosystems and the potential impact of changes within the web. For instance, the removal or addition of a species can significantly alter the flow of energy and the stability of the system as a whole. Therefore, food webs are essential tools for ecologists studying ecosystem health and sustainability.