Science - 2018-19

LS.6 - Ecosystems & Co-dependence

The student will investigate and understand that organisms within an ecosystem are dependent on one another and on nonliving components of the environment. Key concepts include
a) the carbon, water, and nitrogen cycles;
b) interactions resulting in a flow of energy and matter throughout the system;
c) complex relationships within terrestrial, freshwater, and marine ecosystems; and
d) energy flow in food webs and energy pyramids.

Bloom's Levels:  Analyze; Understand

Adopted: 2010


  • Ecosystems are composed of biotic and abiotic components and are complex, interconnected systems.
  • Plants and animals, including humans, interact with and depend on each other and their environment to satisfy their basic needs.

  • I can explain how populations help one another, such as how certain plants should planted near one another.
  • I can explain how over-hunting deer may have a negative impact on the local ecosystem.
  • I can identify and explain the similarities and differences between life on land and in water.
  • I can explain how and why organisms are needed to support one another.


  • Many important elements and compounds cycle through the living and nonliving components of the environment as a chain of events that continuously repeats.
  • Materials are recycled and made available through the action of decomposers.
  • In order to understand how an ecosystem functions, one must understand the concept of a system and be able to envision models of systems.
  • To analyze the interactions resulting in a flow of energy and matter throughout the ecosystem, one must identify the elements of the system and interpret how energy and matter are used by each organism.
  • Energy enters an ecosystem through the process of photosynthesis and is passed through the system as one organism eats and is, in turn, eaten. This energy flow can be modeled through relationships expressed in food webs.
  • The amount of energy available to each successive trophic level (producer, first-order consumer, second-order consumer, third-order consumer) decreases. This can be modeled through an energy pyramid, in which the producers provide the broad base that supports the other interactions in the system.


In order to meet this standard, it is expected that students will

a)  differentiate among key processes in the water, carbon, and nitrogen cycles and relate how organisms, from bacteria and fungi to third-order consumers, function in these cycles.

b)  observe and identify common organisms in ecosystems and collect, record, and chart data concerning the interactions of these organisms (from observations and print and electronic resources).

classify organisms found in local ecosystems as producers or first-, second-, or third-order consumers. Design and construct models of food webs with these organisms.

observe local ecosystems and identify, measure, and classify the living and nonliving components.

c)  identify examples of interdependence in terrestrial, freshwater, and marine ecosystems.

d)  determine the relationship between a population’s position in a food web and its size.

apply the concepts of food chains, food webs, and energy pyramids to analyze how energy and matter flow through an ecosystem.

a, b, c, d)  design an investigation from a test table question related to food webs. The investigation may be a complete experimental design or may focus on systematic observation, description, measurement, and/or data collection and analysis.

analyze and critique the experimental design of basic investigations related to food webs.


ecosystem, producer, consumer, decomposer, food chain, food web, energy pyramid, herbivore, carnivore, omnivore, scavenger, carbon cycle, nitrogen cycle, water cycle, terrestrial ecosystem, marine ecosystem, freshwater ecosystem

Updated: Jun 29, 2018