What concept describes the belief that all species are connected in a hierarchical order?

The Great Chain of Being is the concept that articulates the belief in a hierarchical structure of all species, where each organism has its place in a connected order that ranges from the simplest forms of life to the most complex. This idea originates from ancient philosophical and theological thought, suggesting that all living being types are interconnected through a divine arrangement, often ranked from inanimate objects to higher entities like angels and God.

This hierarchical model emphasizes not only a relationship between different forms of life but also underscores the notion of a continuum, reflecting an order in nature that was thought to be designed. In contrast, natural selection focuses on the mechanisms of evolution rather than providing a structure of beings, the food chain illustrates trophic relationships among organisms rather than their hierarchical categorization, and ecosystems refer to the interactions between organisms and their environment without implying a strict order among the species present.