Ecology, or ecological science, is the scientific study of the distribution and abundance of living organisms and how the distribution and abundance are affected by interactions between the organisms and their environment. The environment of an organism includes both physical properties, which can be described as the sum of local abiotic factors such as solar insolation, climate and geology, as well as the other organisms that share its habitat.

The following outline is provided as an overview of and topical guide to ecology:

Essence of ecology

Main article: Ecology

Subdisciplines of ecology, and subdiscipline classification

Ecology is a broad discipline comprising many sub-disciplines. The field of ecology can be sub-divided according to several classification schemes:

By level of complexity or scope

Arranged from lowest to highest complexity:

  • Ecophysiology/Behavioral ecology – examine adaptations of the individual to its environment.
  • Population ecology – studies the dynamics of populations of a single species.
  • Community ecology – (or synecology) focuses on the interactions between species within an ecological community.
  • Ecosystem ecology – studies the flows of energy and matter through the biotic and abiotic components of ecosystems.
  • Systems ecology – is an interdisciplinary field focusing on the study, development, and organization of ecological systems from a holistic perspective.
  • Landscape ecology – examines processes and relationship across multiple ecosystems or very large geographic areas.

By organisms under study

By biome under study

By geographic or climatic area under study

By spatial scale under study

  • Global ecology – which examines ecological phenomena at the largest possible scale, addressing macroecological questions;
  • Landscape ecology – which studies the interactions between discrete elements of a landscape;
  • Landscape limnology – the spatially-explicit study of aquatic ecosystems (e.g., rivers, lakes, and wetlands) as they interact with the aquatic, terrestrial, and human components of landscapes to determine the effects of pattern on ecosystem processes across spatial scales;
  • Spatial ecology – which identifies spatial patterns and their relationships to ecological events;
  • Macroecology – the study of large scale phenomena;
  • Microecology – the study of small scale phenomena;
  • Microbial ecology
  • Molecular ecology

By ecological aspects or phenomena under investigation

  • Chemical ecology – which deals with the ecological role of biological chemicals used in a wide range of areas including defense against predators and attraction of mates;
  • Ecophysiology – which studies the interaction of physiological traits with the abiotic environment;
  • Ecotoxicology – which looks at the ecological role of toxic chemicals (often pollutants, but also naturally occurring compounds);
  • Evolutionary ecology – or ecoevolution which looks at evolutionary changes in the context of the populations and communities in which the organisms exist;
  • Fire ecology – which looks at the role of fire in the environment of plants and animals and its effect on ecological communities;
  • Functional ecology – the study of the roles, or functions, that certain species (or groups thereof) play in an ecosystem;
  • Genetic ecology
  • Soil ecology – the ecology of the pedosphere;

By technique used for investigation

By philosophical approach

Ecology-involved interdisciplinary fields

Biogeographic regions


The World Wildlife Fund (WWF) developed a system of eight biogeographic realms (ecozones):


Ecozones are further divided into ecoregions. The World has over 800 terrestrial ecoregions. See Lists of ecoregions by country.

History of ecology

Main article: History of ecology

General ecology concepts

Ecology lists

Main article: List of ecology topics

See also

External links

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