macroorganisms

Macroorganisms are organisms large enough to be seen with the unaided eye, distinguishing them from microorganisms which require magnification. While exact thresholds vary by field, macroorganisms are typically visible without a microscope and range from a few millimeters to meters in size.

The category includes many plants, animals, fungi, and some macroalgae and other macroscopic organisms. Examples are trees, flowering plants, insects, birds, mammals, mushrooms, and kelp. Many macroorganisms are mobile; others are sessile and form habitats, such as corals or barnacles.

Ecologically, macroorganisms perform a variety of roles as producers, consumers, or decomposers. They structure ecosystems, influence nutrient cycles, and support biodiversity. In soils, macrofauna like earthworms aid aeration and mixing; in aquatic systems, large animals and macrophytes shape communities and energy flow.

In research, macroorganisms are central to ecology, conservation biology, biogeography, and paleontology. The study of their distribution and interactions at broad scales is called macroecology. The term helps distinguish studies of organismal biology and ecosystem processes from investigations focused on microscopic life.