Levels of Ecological Organization

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Organism Noun

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[or-guh-niz-uhm]

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Organism

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An individual living being, such as an animal or plant, representing the smallest, most fundamental level of ecological organization.

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Example: This image shows a single-celled amoeba, which is one complete, individual living thing. An organism is the first level of ecological organization.

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Species Noun

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[spee-sheez]

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Species

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A group of closely related organisms that are very similar to each other and are capable of interbreeding to produce fertile offspring.

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Example: This image shows three different animals, each representing a unique species, which is a group of organisms that can reproduce with each other.

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Population Noun

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[pop-yuh-ley-shuhn]

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Population

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A group of individuals of the same species that live together in the same geographical area and interact with one another.

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Example: This image shows a population as a group of the same type of organism (fish), distinguishing it from a single organism and a multi-species community.

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Community Noun

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[kuh-myoo-ni-tee]

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Community

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All of the different populations of various species that live together and interact within a particular habitat or area.

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Example: This image shows different populations of organisms, like hawks, snakes, and rabbits, all living and interacting together in one area, forming a community.

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Ecosystem Noun

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[ee-koh-sis-tuhm]

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Ecosystem

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A biological community of interacting organisms (biotic) and their non-living physical environment (abiotic) functioning as a single unit.

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Example: An ecosystem includes living things (plants, animals, decomposers) and non-living things (like sunlight) interacting, as energy flows from the sun to organisms.

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Biosphere Noun

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[bahy-oh-sfeer]

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Biosphere

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The part of the planet, including land, water, and the atmosphere, in which life exists and ecological processes occur.

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Example: This diagram shows that the biosphere is the part of Earth where life exists, encompassing the land (lithosphere), water (hydrosphere), and air (atmosphere).

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Ecologist Noun

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[ih-kol-uh-jist]

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Ecologist

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A scientist who specializes in ecology, studying the complex relationships between living organisms and their surrounding natural environment.

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Example: An ecologist is a scientist who studies the environment. This image shows an ecologist collecting a water sample from a stream to analyze its health.

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Biotic Adjective

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[bahy-ot-ik]

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Biotic

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Relating to or resulting from living things; the living or once-living components of an ecosystem, such as plants and animals.

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Example: Biotic factors are all the living or once-living parts of an ecosystem, such as plants (producers), animals (consumers), and fungi or bacteria (decomposers).

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Abiotic Adjective

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[ey-bahy-ot-ik]

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Abiotic

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Relating to the non-living physical and chemical parts of an environment, such as sunlight, temperature, soil, and water.

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Example: This chart shows examples of abiotic, or non-living, factors in an ecosystem, such as water, sunlight, air, soil, and temperature.