biotic

Biotic describes the living components of an environment or the processes associated with living organisms. The term, derived from the Greek bios for life, is used in biology and ecology to refer to the organisms themselves and the interactions among them that influence where species occur and how populations change. Biotic factors include plants, animals, fungi, bacteria, archaea, and other living organisms, as well as the relationships that connect them.

Biotic interactions are diverse. They include predation, herbivory, competition for resources, parasitism, mutualism, and commensalism. Through these interactions, energy and nutrients move through ecosystems via trophic levels: producers (autotrophs such as plants and algae), consumers (heterotrophs such as herbivores and carnivores), and decomposers (fungi and many bacteria). Biotic factors help determine community structure, species diversity, and the resilience of ecosystems to change.

Biotic conditions operate alongside abiotic factors—nonliving elements such as climate, soil, water, and nutrients—to shape habitats. Population dynamics are influenced by biotic potential (the maximum rate of growth under ideal conditions) and by environmental resistance from limiting resources and interactions with other organisms. Disturbances that alter biotic components, such as invasive species or disease, can lead to shifts in community composition.