Contributed by: New York State Alternative Assessment in Science
Project (NYSED)
Student #1
Task: At this station, you will be interpreting data presented
in graphs.
Background
Paramecia are found in stagnant pond water. Excess water is regularly
removed from these organisms by the pumping action of contractile
vacuoles. Paramecia were place in 3 different solutions: Pond water
(containing 95% water and various dissolved minerals), Solution
A, and Solution B. While observing a contractile vacuole using the
high power magnification (400x) of a microscope, a student counted,
in 30 second intervals, the number of times the contractile vacuole
pumped water out of the cell and repeated his counts in the three
solutions. The results are presented in the graphs below:
Base your answers to the following questions on the previous graphs.
- Using complete sentences describe your observations of the behavior
of the contractile volumes in each solution:
- Think about the relationship between the concentration of dissolved
materials in the two solutions and pond water. Use the following
terms to complete the two statements below.
Same as OR Greater
than OR Less than
- What would you add to Solution A to restore the vacuole contraction
to the same rate as in pond water?
- Using complete sentences, suggest and explanation to your answer
to question 3:
- Using complete sentences, what would you add to Solution B to
restore the vacuole contraction to the same rate as in pond water?
- Using complete sentences, suggest an explanation to your answer
to question 5.
- What will happen to a paramecium if the contractile vacuole
failed to remove the excess water?
- Using complete sentences explain how you reached your prediction
in question 7.
- Name two (2) biological processes which take place in this investigation.
Scoring
Circle the student's score for each part of the exercise. Add the
points for each part and write the total score at the bottom of
the scoring form.
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