Science - 2018-19

LS.8 - Relationships in Communities

The student will investigate and understand interactions among populations in a biological community. Key concepts include

a) the relationships among producers, consumers, and decomposers in food webs;

b) the relationship between predators and prey;

c) competition and cooperation;

d) symbiotic relationships; and

e) niches.

Bloom's Levels:  Analyze; Understand

Adopted: 2010


  • All living things require energy.
  • Energy flows from the sun through producers to consumers.

  • I can explain why fungus and other decomposers are essential to humans.
  • I can predict what will happen to the mouse population if more hawks are introduced to the community.
  • I can explain why barnacles on whales are good, but tapeworms in humans are bad.
  • I can determine where an animal likely lives based on its characteristics.


  • Organisms or populations that rely on each other for basic needs form interdependent communities.
  • Energy resources of a community are shared through the interactions of producers, consumers, and decomposers.
  • The interaction between a consumer that hunts for another consumer for food is the predator-prey relationship.
  • In a community, populations interact with other populations by exhibiting a variety of behaviors that aid in the survival of the population.
  • Organisms may exist as members of a population; populations interact with other populations in a community.
  • Populations of one species may compete with populations of other species for resources. Populations of one species may also cooperate with populations of other species for resources.
  • A symbiotic relationship may exist between two or more organisms of different species when they live and work together.
  • Symbiotic relationships include mutualism (in which both organisms benefit), commensalism (in which one organism benefits and the other is unaffected), and parasitism (in which one organism benefits and the other is harmed).
  • Each organism fills a specific role or niche in its community.


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

a)  identify the populations of producers, consumers, and decomposers and describe the roles they play in their communities.

b)  generate predictions based on graphically represented data of predator-prey populations.

c)  generate predictions based on graphically represented data of competition and cooperation between populations.

d)  differentiate between the types of symbiosis and explain examples of each.

e)  infer the niche of organisms from their physical characteristics.

a, b, c, d, e)  interpret, analyze, and evaluate data from systematic studies and experiments concerning the interactions of populations in an ecosystem.

predict the effect of population changes on the food web of a community.

design an investigation from a testable question related to interactions among populations. The investigation may be a complete experimental design or may focus on systematic observation, description, measurement, and/or data collection and analysis.


population, community, cooperation, competition, symbiotic relationship, mutualism, commensalism, parasitism, niche, predator, prey, social hierarchy, territorial imperative, limiting factors, carrying capacity

Updated: Jun 29, 2018