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Predator/Prey Relationship
Administration Procedures
Contributed by: Council of Chief State School Officers (CCSSO)


Students study a table containing population data covering a 28 year period for snowshoe hare and lynx in a certain area of Canada. The students are asked to create a graph of the data to facilitate accurate analysis, then to use the research data to write a brief response to a proposal to reduce the lynx population.

This task is designed to take students approximately 40-50 minutes to completely.

Overall Task Content Area:

Life Science

Specific Knowledge Areas:

Populations and ecosystems

Performance Expectations:

  • conducting investigations
  • gathering, organizing, and representing data
  • formulating conclusions from investigational data
  • applying scientific principles to develop explanations and solve new problems

National Science Education Standards:

8 C LS 4:  Populations and ecosystems:  Grades 5-8
4.4 The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition. Given adequate biotic and abiotic resources and no disease or predators, populations (including humans) increase at rapid rates. Lack of resources and other factors, such as predation and climate, limit the growth of populations in specific niches in the ecosystem.

8 A SI 1:  Abilities of scientific inquiry:  Grades 5-8
1.3 Employ simple equipment and tools to gather data and extend the senses. In early years, students develop simple skills, such as how to observe, measure, cut, connect, switch, turn on and off, pour, hold, tie, and hook. Beginning with simple instruments, students can use rulers to measure the length, height, and depth of objects and materials; thermometers to measure temperature; watches to measure time; beam balances and spring scales to measure weight and force; magnifiers to observe objects and organisms; and microscopes to observe the finer details of plants, animals, rocks, and other materials. Children also develop skills in the use of computers and calculators for conducting investigations.

(Use the "hot" link on the PALS home page to check the full text of related National Science Education Standards, if desired.)

National Council of Teachers of Mathematics:

AL4: Analyze change in various contexts:
Grades 6-8 e. use graphs to analyze the nature of changes in quantities in linear relationships

AL1: Understand patterns, relations and functions:
Grades 6-8 f. represent, analyze, and generalize a variety of patterns with tables, graphs, words, and, when possible, symbolic rules

DAP3: Develop and evaluate inferences and predictions that are based on data:
Grades 6-8 c. use observations about differences between two or more samples to make conjectures about the populations from which the samples were taken

PS2: Solve problems that arise in mathematics and in other contexts:
Grades 6-8

RP3: Develop and evaluate mathematical arguments and proofs:
Grades 6-8

COM4: Use the language of mathematics to express mathematical ideas precisely:
Grades 6-8

REP3: Use representations to model and interpret physical, social, and mathematical ideas:
Grades 6-8

General Teacher Instructions:

You may choose to have students work alone or in small groups to complete the first part of the exercise. This would include the initial data analysis and the creation of a line graph for both data sets. In any case, students should work alone to complete questions #1 and #2 where constructed responses are required. If students work initially in groups, allow no more than 20 minutes for them to complete the graph. At that point, students should be told that they are to work alone to complete the remaining parts of the test and that there is to be no more talking. Whether or not they are just beginning their individual work, remind students that they now have 25 minutes to complete the individual activity.

Students should be ready to work as soon as the period begins. Group assignments, if used, should be made in advance.

Materials in Kits:

No materials other than the student test papers are needed for this exercise.

Advance Preparation:

Group assignments, if used, should be made in advance.


  • Be careful.
  • Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks.


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