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  2. List of ecoregions in the United States (EPA) - Wikipedia

    en.wikipedia.org/wiki/List_of_ecoregions_in_the...

    The classification system has four levels, but only Levels I and III are on this list. Level I divides North America into 15 broad ecoregions; of these, 12 lie partly or wholly within the United States. Fifty Level II regions were created to allow for a narrower delineation of Level I areas. Three level I areas were not subdivided for level 2. [2]

  3. Ecological unit - Wikipedia

    en.wikipedia.org/wiki/Ecological_unit

    Ecological units refer to specific levels or degrees of organization within ecological systems. The units that are most commonly used and discussed within ecological systems are those at the levels of individuals, populations , communities , and ecosystems . [ 1 ]

  4. Biological organisation - Wikipedia

    en.wikipedia.org/wiki/Biological_organisation

    The higher levels of this scheme are often referred to as an ecological organisation concept, or as the field, hierarchical ecology. Each level in the hierarchy represents an increase in organisational complexity , with each "object" being primarily composed of the previous level's basic unit. [ 2 ]

  5. Ecological pyramid - Wikipedia

    en.wikipedia.org/wiki/Ecological_pyramid

    A pyramid of biomass shows the relationship between biomass and trophic level by quantifying the biomass present at each trophic level of an ecological community at a particular time. It is a graphical representation of biomass (total amount of living or organic matter in an ecosystem) present in unit area in different trophic levels.

  6. Trophic level - Wikipedia

    en.wikipedia.org/wiki/Trophic_level

    Food webs largely define ecosystems, and the trophic levels define the position of organisms within the webs. But these trophic levels are not always simple integers, because organisms often feed at more than one trophic level. [14] [15] For example, some carnivores also eat plants, and some plants are carnivores. A large carnivore may eat both ...

  7. Ecosystem ecology - Wikipedia

    en.wikipedia.org/wiki/Ecosystem_ecology

    Population, community, and physiological ecology provide many of the underlying biological mechanisms influencing ecosystems and the processes they maintain. Flowing of energy and cycling of matter at the ecosystem level are often examined in ecosystem ecology, but, as a whole, this science is defined more by subject matter than by scale.

  8. Ecosystem - Wikipedia

    en.wikipedia.org/wiki/Ecosystem

    An ecosystem (or ecological system) is a system formed by organisms in interaction with their environment. [ 2 ] : 458 The biotic and abiotic components are linked together through nutrient cycles and energy flows.

  9. Ecological classification - Wikipedia

    en.wikipedia.org/wiki/Ecological_classification

    Ecological classification or ecological typology is the classification of land or water into geographical units that represent variation in one or more ecological features. . Traditional approaches focus on geology, topography, biogeography, soils, vegetation, climate conditions, living species, habitats, water resources, and sometimes also anthropic factors.