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The study of interactions that take place between organisms and their environment.

It explains how living organisms affect each other and the world they live in.

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Habitat is the place an organism lives.

Niche is the unique position occupied by a species both in terms of its physical use of its habitat and its function within an ecological community. “total way of life” or its “role” in the

ecosystem.

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Abiotic factors- the nonliving parts of an organism’s environment. affect an organism’s life Ex: air currents, temperature, moisture, light,

and soil.

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Biotic factors- all the living organisms that inhabit an environment.

All organisms depend on others directly or indirectly for food, shelter, reproduction, or protection.

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Ecologists have organized the interactions of organisms, based on different levels of complexity.

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Atom Molecule Organelle Cell Tissue Organ System Organism Population Community Ecosystem Biosphere

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Organism:An individual living thing that demonstrates these characteristics: • Made of cells, • Metabolizes,• Reproduces,• Responds to Stimuli• Evolves• Heredity• Homeostasis

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Population:A group of organisms, all of the same species, which interbreed and live in the same place at the same time.

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Community:All the populations of different species that live in the same place at the same time.

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Ecosystem: Populations of plants and animals that interact with each other in a given area with the abiotic components of that area.

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Biosphere:The portion of Earth that supports life.

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