👉 In the context of science, "microcosmos" refers to a small or miniature environment within which a larger system operates. Microcosms are often considered to be the smallest level of organization and complexity in nature, reflecting the smallest levels at which life occurs on Earth. Microcosmic systems differ from macrocosmic systems (which include larger ecosystems) because they are more closely tied to their environment. In microcosm terms, things like bacteria or viruses live within a single cell. The environment