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, representing the smallest and most basic level of ecological organization in any given environment.

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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 genetically similar organisms that can breed with one another and produce fertile offspring under natural conditions.

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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 organisms belonging to the same species that live in the same geographical area and interact together.

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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 and interact with one another within a particular 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 community of living organisms (biotic) interacting with the non-living (abiotic) chemical and physical components of their environment.

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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 the land, water, and atmosphere, in which all known life exists.

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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 studies the complex relationships between living organisms and their interactions with the 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 the living or once-living components of an ecosystem, including all of the organisms within that environment.

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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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The non-living chemical and physical parts of an ecosystem that influence living organisms and the environment's functions.

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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.