Ohio Graduation Test for Science – March 2007
Annotated Item 44
Standard and Benchmark Assessed:
Standard:
Benchmark:
Life Sciences
F. Explain the structure and function of ecosystems and relate how ecosystems
change over time.
Multiple Choice Question:
Use the information to answer questions 42 – 44.
Hare and Lynx Populations
In a classic study of predator-prey interactions, the numbers of snowshoe hare pelts and lynx
pelts sold to a trading company by trappers were recorded over a period of 100 years. Both
lynx and hare populations appear to oscillate in a regular pattern over a period of about ten
years. One explanation for this pattern is that heavy predation reduces the snowshoe hare
population, which in turn reduces the lynx population. More recently, scientists have proposed
that the hare population oscillates due to diseases caused by overcrowding or by the effects of
its own feeding activities on vegetation.
Source: Ohio Department of Education
August 07
Ohio Graduation Test for Science – March 2007
Annotated Item 44
44.
What would prevent the lynx population from declining along with the hare population?
A.
B.
C.
D.
an extremely harsh winter
an influx of other hare predators
an abundant alternate food source
an outbreak of disease among hares
Commentary:
This multiple choice question asks students to predict and identify what would prevent the lynx
population from declining along with the hare population. Students can observe that the data
shows a direct connection between hares and lynx. As the number of hares increases, the lynx
numbers increase and the opposite is also true. Students should recognize that these
simultaneous fluctuations in population size indicate that the hare are a primary food source for
the lynx. Answer choice C is correct because if the lynx had an alternate source of food, the
lynx population would not be expected to decline dramatically with the hare population. Answer
choice A is incorrect because an extremely harsh winter would be likely to negatively impact
both the hare and lynx populations. Answer choice B is incorrect because an influx of other
hare predators would negatively impact the lynx population by introducing competition for the
lynx’s food source. Answer choice D is incorrect because disease among the hares would
reduce the food source of the lynx and could result in a decrease in the lynx population.
This question is classified as Communicating Understanding / Analyzing Science Information
because the task requires students to evaluate the data for hare and lynx populations to
determine the relationship between the two organisms and predict how changes in one
population or in other environmental factors will impact this relationship.
Performance Data:
The percent of public school students selecting answer choice C for question 44 on the March
2007 Ohio Graduation Test was 66%.
Keywords:
ecosystem, population
Source: Ohio Department of Education
August 07