What is a hierarchical series of organisms each dependent on the next as a source of food called?

A hierarchical series of organisms each dependent on the next as a source of food is referred to as a food chain. This concept illustrates how energy and nutrients flow through an ecosystem, beginning with primary producers (like plants) that convert sunlight into energy through photosynthesis. Primary consumers then feed on these producers, followed by secondary and tertiary consumers that prey on the primary consumers. Each level in the food chain demonstrates a direct line of nutritional dependency and reflects the transfer of energy from one organism to another.

In contrast, a food web would depict a more complex network of interactions with various organisms consuming multiple food sources, rather than a linear sequence. A food pyramid visually represents the relationship and energy distribution within various levels of an ecosystem, but does not specifically focus on the direct dependencies between organisms like a food chain does. Energy flow describes the movement of energy through an ecosystem but does not specify the hierarchical relationships between individual organisms.