biotas

Biotas are the assemblage of living organisms in a given place or region, or during a specified time period. The term encompasses all organisms—plants, animals, fungi, and microorganisms—and thus covers the biological component of ecosystems as well as the interactions among species. Biotas are shaped by climate, geology, soils, topography, and history, and they vary across latitudes, altitudes, and habitats. In the same region, biota may change over time due to succession, evolution, and human influence. Biotic communities are often described in terms of biodiversity, including species richness, evenness, and endemism, and are organized into biomes and ecological communities.

In biogeography and ecology, the study of biotas ranges from modern biota, describing current life, to paleobiota, focusing on fossil organisms and past ecosystems. Marine biotas include planktonic and epifaunal organisms; terrestrial biotas range from tropical rainforest to deserts; freshwater biotas include fish, invertebrates, and aquatic plants. Biotas interact through food webs, symbioses, and competition, contributing to ecosystem functions such as primary production, nutrient cycling, and pollination.

Human activity can rapidly alter biotas by habitat destruction, climate change, pollution, invasive species, and overexploitation, often reducing biodiversity and shifting community composition. Conservation biology seeks to preserve biotas and their ecological processes, often by protecting habitats, promoting connectivity, and preventing invasive species.