The picture below shows a pond ecosystem. Use this picture and what you know about the things in it to
answer the questions in this section.
Suppose that one spring a new type of large fish was put into the pond. So many were put in that
there were twice as many fish as before. By the end of the summer, what would happen to the large
fish that were already in the pond?
Explain why you think these new large fish would have this effect.
NAEP released item, grade 8
Scoring Guide
Score & Description
Correct
Student provides a response showing clear understanding of competition and its effect on
population.
Partial
Student provides a response that shows an understanding of competition, but not of the
consequences.
OR
Student provides a response that shows a reasonable consequence and gives a plausible reason
not based on competition.
Incorrect
Student provides a response that shows no understanding of the concept of interspecific
competition, answering that there will be more of the large fish already in the pond, or that the two
kinds of fish would be friends, etc.
OR
Student responds that one type of fish would die and gives no reason or an implausible reason.
Correct - Student Response
Suppose that one spring a new type of large fish was put into the pond. So many were put in that
there were twice as many fish as before. By the end of the summer, what would happen to the
large fish that were already in the pond?
Explain why you think these new large fish would have this effect.
Scorer Comments:
Student response mentions competition for food and the possible dying out of the original large fish
as a result.
NAEP released item, grade 8
Suppose that one spring a new type of large fish was put into the pond. So many were put in that
there were twice as many fish as before. By the end of the summer, what would happen to the
large fish that were already in the pond?
Explain why you think these new large fish would have this effect.
Scorer Comments:
Student response mentions competition for space and the possible outcome.
Partial - Student Response
Suppose that one spring a new type of large fish was put into the pond. So many were put in that
there were twice as many fish as before. By the end of the summer, what would happen to the
large fish that were already in the pond?
Explain why you think these new large fish would have this effect.
Scorer Comments:
Student response mentions the effect of reduction of fish population due to limited food resources,
but does not specifically mention competition.
NAEP released item, grade 8
Suppose that one spring a new type of large fish was put into the pond. So many were put in that
there were twice as many fish as before. By the end of the summer, what would happen to the
large fish that were already in the pond?
Explain why you think these new large fish would have this effect.
Scorer Comments:
Student response states the effect of reduction of fish population due to competition, but does not
specifically state the purpose of the competition.
Incorrect - Student Response
Suppose that one spring a new type of large fish was put into the pond. So many were put in that
there were twice as many fish as before. By the end of the summer, what would happen to the
large fish that were already in the pond?
Explain why you think these new large fish would have this effect.
Scorer Comments:
Student response states the effect of reduction of fish population, but gives an implausible reason.
NAEP released item, grade 8
Suppose that one spring a new type of large fish was put into the pond. So many were put in that
there were twice as many fish as before. By the end of the summer, what would happen to the
large fish that were already in the pond?
Explain why you think these new large fish would have this effect.
Scorer Comments:
Student response states the effect of reduction of fish population, but gives a vague reason.
2000 National Performance Results
Score
Percentage of Students
Incorrect
39%
Partial
53%
Correct
4%
Omitted
4%
Off task 1%
Note:
•
•
These results are for public and nonpublic school
students.
Percentages may not add to 100 due to rounding.
The Fields of Science: Life Sciences (Sub content classification: Ecology)
Knowing and Doing Science : Practical Reasoning
NAEP released item, grade 8
The Fields of Science
Life Sciences
This question measures basic knowledge and understanding of the following:
Knowing and Doing Science
Practical Reasoning
Practical reasoning probes students' abilities to use and apply science understanding in new, realworld applications.
NAEP released item, grade 8