In paleoecology and ecological forecasting, a no-analog community or climate is one that is compositionally different from a (typically modern) baseline for measurement. Alternative naming conventions to describe no-analog communities and climates may include novel, emerging, mosaic, disharmonious and intermingled. Modern climates, communities and ecosystems are often studied in an attempt to understand no-analogs that have happened in the past and those that may occur in the future. This use of a modern analog to study the past draws on the concept of uniformitarianism. Along with the use of these modern analogs, actualistic studies and taphonomy are additional tools that are used in understanding no-analogs. Statistical tools are also used to identify no-analogs and their baselines, often through the use of dissimilarity analyses or analog matching Study of no-analog fossil remains are often carefully evaluated as to rule out mixing of fossils in an assemblage due to erosion, animal activity or other processes. No-analog climates Conditions that are considered no-analog climates are those that have no modern analog, such as the climate during the last glaciation. Glacial climates varied from current climates in seasonality and temperature, having an overall more steady climate without as many extreme temperatures as today's climate. Climates with no modern analog may be used to infer species range shifts, biodiversity changes, ecosystem arrangements and help in understanding species fundamental niche space. Past climates are often studied to understand how changes in a species' fundamental niche may lead to the formation of no analog communities. Seasonality and temperatures that are outside the climates at present provide opportunity for no-analog communities to arise, as is seen in the late Holocene plant communities. Evidence of deglacial temperature controls having significant effects on the formation of no-analog communities in the midwestern United States provides example of how intertwined climate and species assemblage are when studying no-analogs. No-analog communities No-analog communities are defined by the existence of extant species in groupings that are not currently seen in modern biomes, or populations that have history of species assemblages that are no longer seen in the modern world. Formation of no-analog communities can be due to multiple factors, including climate conditions, environmental changes, human action, disease or species interactions. Migrations of species causes displacement and colonization into areas that may have been outside of what was known to be their fundamental niche, such as northern species moving south and mountain fauna being removed