Final answer:
A food web shows the complex interactions between species within an ecosystem, while a food chain represents a simplified version of these interactions.
Step-by-step explanation:
A food web is a diagram that shows feeding interactions between many organisms in an ecosystem through multiple intersecting pathways. It represents the complex interactions between different species within an ecosystem. In contrast, a food chain is a diagram that shows feeding interactions in an ecosystem through a single pathway, which is a more simplified representation of ecosystem structure.