organic litter made up of dead organisms, their parts, and waste

a chemical in food that helps keep an organism alive and active

referring to water

microscopic animals in aquatic environments

cells that send messages to the brain when they receive stimuli

an organism that breaks down plant and animal material into simple chemicals

microorganisms that act as decomposers

an organism that lacks chlorophyll and gets nutrients from dead or living organisms

an organism that cannot make its own food. they eat other organisms

microscopic plantlike organisms in aquatic environments that produce their own food

referring to land

an organism, such as a plant or algae, that makes its own food

the feeding relationships among all the organisms in an ecosystem. Arrows show the flow of matter and energy from one organism to another

a description of the feeding relationships between organisms in an environment

a community of organisms interacting with each other and with the nonliving environment

a system of interacting living organisms on Earth

the layer of gases surrounding Earth

the interacting water on, under, and above Earth's surface

Earth's core, mantle, and crust

to act upon one another

the system inside a larger system

a collection of interacting parts