Ecology

• It is a branch of science which studies the interactions among organisms and between the organism and its physical (abiotic) environment.

Organisational Levels of Ecology

• Organism: Living component of the environment at individual level is called organism.
• Ecology at the organismic level is physiological ecology which reveals how different organisms are adapted to their environments. The organism is the smallest level of ecological hierarchy.
• Population: Population is defined as the sum total of all individuals of a species in a specific geographical area.
• Species: The species are the group of individuals of one or more populations which resemble each other and can interbreed among themselves.
• Biotic community: The assemblage of the populations of different species present in an area that interact among themselves are called biotic community.
• Ecosystem: The sum total of the biotic (living) and abiotic (non-living) components of a particular geographical area being integrated through exchange of energy and recycling of nutrients.
• Biome: The large unit of environment consisting of a major vegetation type and its associated fauna in a specific climatic zone is called a biome.
• Biosphere: All the ecosystems of the world are collectively called biosphere.