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Stimulus/Response in Invertebrates
Administration Procedures
Grades 5-8 Performance Task
Contributed by: Oregon State Department of Education


Students will devise simple experiments to test how a slug's or earthworm's structures allow it to accomplish various functions for survival.

The task assesses students' understanding of scientific inquiry including the following skills: observation, background research, scientific procedures (including investigation design, measurement techniques, and error analysis), data collection, data display, scientific questions, formulating a hypothesis.

This task is designed to take students approximately 4 hours or four 45 minute class periods.

Overall Task Content Area:

Life Science

Specific Knowledge Areas:

Relationship and interaction of organ systems

Performance Expectations:

  • conducting investigations
  • using equipment
  • gathering, organizing, and representing data
  • formulating conclusions from investigational data

National Science Education Standards:

8 A SI 1: Abilities necessary to do scientific inquiry: Grades 5-8

1.2 Design and conduct a scientific investigation. Students should develop general abilities, such as systematic observation, making accurate measurements, and identifying and controlling variables. They should also develop the ability to clarify their ideas that are influencing and guiding the inquiry, and to understand how those ideas compare with current scientific knowledge. Students can learn to formulate questions, design investigations, execute investigations, interpret data, use evidence to generate explanations, propose alternative explanations, and critique explanations and procedures.

1.4 Develop descriptions, explanations, predictions, and models using evidence. Students should base their explanation on what they observed, and as they develop cognitive skills, they should be able to differentiate explanation from description providing causes for effects and establishing relationships based on evidence and logical argument. This standards requires a subject knowledge base so the students can effectively conduct investigations, because developing explanations establishes connections between the content of science and the contexts within which students develop new knowledge.

1.7 Communicate scientific procedures and explanations. With practice, students should become competent at communicating experimental methods, following instructions, describing observations, summarizing the results of other groups, and telling other students about investigations and explanations.

8 C LS 3: Regulation and behavior: Grades 5-8

3.3 Behavior is one kind of response an organism can make to an internal or environmental stimulus. A behavioral response requires coordination and communication at many levels, including cells, organ systems, and whole organisms. Behavioral response is a set of actions determined in part by heredity and in part from experience.

(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:

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

General Instructions to the Teacher:

This task is designed to take students approximately 4 hours or four 45 minute class periods to complete. .

Students should be ready to work as soon as periods begin. A central supply area, if needed, should be easily accessible. All supplies should be clearly labeled.

Materials for "Stimulus/Response in Invertebrates":

The student will need:

  • shallow pan
  • flashlight (light source)
  • measurement tools
  • paper towels
  • pencil
  • hand lens
  • water
  • vinegar
  • glass plate
  • a living invertebrate

Advance Preparation:

Possible Context: Life Science including study of organs and organ systems, animal behavior, live animal study/debate.

  1. Inquiry Activity: OBSERVATION--What happens when you smell your favorite food? Your mouth waters.
  2. DISCUSS--stimulus and response of organisms. Some response is instantaneous, while others are long term (maybe generations). The earthworm has no eyes, ears or nose. Can it still sense light, sound, and odor in addition to other stimuli?
  3. Observe and sketch your animal.
  4. Describe the physical features of your animal.


  • 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.


  • Helpful Resource: National Science Teachers Association, Science Educator's Guide to Assessment, 1998, p.107.



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