ACT science practice test 43

Directions: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.

You are NOT permitted to use a calculator on this test.


In 1906, the Kaibab Plateau in northern Arizona was declared a federal game refuge by President Theodore Roosevelt. Before this time, the Kaibab was home to mule deer, cattle, sheep, and a variety of predators. The approximately 4,000 Rocky Mountain deer were an important source of food for the wolves, coyotes, bears, mountain lions, and bobcats that lived on the Kaibab and competed with sheep, horses, and cattle for the limited grass resources of the plateau.

When the game refuge was created, all deer hunting was banned in an attempt to protect the "finest deer herd in America." In 1907, the U.S. Forest Service began to exterminate the natural predators of the deer. With the deer freed from the checks and balances of predators, the population began to multiply. By the early 1920s, scientists estimated that there were as many as 100,000 deer on the plateau.

Sheep and cattle were also banned from the Kaibab. Signs of overgrazing were everywhere, and disease began to attack the crowded deer population. Hunting was reopened, but it was not enough to reduce the number of deer. Some estimate that as many as 60,000 deer starved to death in the winters of 1925 and 1926.

Two scientists exchange views about "The Kaibab Deer Incident: A Long-Persisting Myth."

Scientist A

The Kaibab Plateau should be a lesson to everyone about the disruption of the predator-prey relationship. This is a classic example of predator control hurting the very species that the wildlife biologists are attempting to help. If the predators had not been removed from the Kaibab Plateau, the deer population would have grown under normal conditions and would not have been subjected to the cruel fate of starvation and disease. This is a moral case that should be heeded by all biologists when considering predator control and presented to biology students in their studies of predator checks in population dynamics.

Scientist B

Predator removal is only a small part of the disaster on the Kaibab and has been grossly overdramatized. The deer population on the plateau grew rapidly because of the increase in food supply after the removal of competitive species. With no sheep and cattle to compete with for grazing, the environment could readily support more deer. The increased food supply allowed the population to grow quickly and to fall just as quickly due to the density-dependent factors of starvation and disease. In fact, data about the peak total number of deer on the plateau are unreliable, and there may have only been 30,000. The factors are more complex than early ecologists believed, but the lesson is still valuable.

*Based on data from C. John Burk, "The Kaibab Deer Incident: A Long-Persisting Myth," BioScience 23, no. 2 (1973): 113-14.

1. Which of the following pieces of information would Scientist A use to support his claim?

A. Before 1906, the Kaibab Plateau had already been overgrazed by the herbivores in the area.
B. It is estimated that between 1907 and 1939, 816 mountain lions, 20 wolves, 7,388 coyotes, and more than 500 bobcats were killed.
C. The U.S. Forest Service reduced the number of livestock grazing permits.
D. In 1924, a committee formed to oversee the situation recommended that all livestock not owned by local residents be removed immediately.

2. Which of the following reflects evidence presented by both Scientist A and Scientist B about the deer situation on the Kaibab Plateau?

A. Competition among herbivores was reduced due to restrictions on grazing.
B. The food chain was disrupted when secondary consumers were reduced.
C. Starvation and disease reduced the herd during the winters of 1925 and 1926.
D. Human intervention in the predator population was the cause of the upsurge in the deer population.

3. Which statement would LEAST likely be attributed to Scientist B?

A. Data about the deer herd are unreliable and inconsistent, and the factors that may have led to an upsurge are hopelessly confounded.
B. Conclusions that have been made about the Kaibab are based on the maximum estimate and evolved by unjustified tampering with original data.
C. This is a classic example of how the effects of disruption of the predator-prey relationship can be seen plainly.
D. The reduction in sheep alone from 1889 to 1908 might have totaled 195,000.

4. The following statements have been made by biologists to describe the Kaibab Plateau situation. On which statement would Scientists A and B be likely to agree?

A. The plateau represents the unforeseen and disastrous possibilities of ignorant interference in natural communities.
B. The Kaibab is a classic example of what happens when people set out to protect prey from their enemies" (sometimes only to preserve them for their human ones) by killing the predators."
C. Man is the most destructive predator alive.
D. This situation is a well-documented example of what can happen when predators are removed from an ecosystem.

5. The views of Scientist A:

A. minimize the role of the bounty placed on predators.
B. emphasize the lack of competition for resources.
C. show a more balanced view of the problem by taking into account all factors that led to the increase in population.
D. are likely to be used by someone trying to illustrate the dangers of removing a species from the food chain.

6. Scientist A would be most likely to support:

A. the introduction of non-native species into an area where there are no natural predators.
B. controlled hunting of predators to protect endangered species.
C. future efforts to reorganize natural ecosystems through human intervention.
D. the view that predators help preserve ecosystems.

7. Scientists A and B tend to agree on:

A. the role of an increase in grass abundance in the increase of the deer population.
B. the role that disease and starvation played in reducing the population.
C. the role of predation in the increase of the deer population.
D. the data to be used to represent the situation on the Kaibab.

8. Which of the following facts would support the view of Scientist B regarding the cause for rapid increase in the deer population?

A. Coyotes were hunted in the thousands.
B. Starvation and disease were rampant from 1924 to 1926.
C. Hunters killed 674 deer in 1924.
D. Sheep and cattle were banned during this time period.

9. Lethal reduction of midsized mammal predators that target duck nests is a method used to increase the duck population available for sport hunters. Which of the following statements would Scientist A most likely make regarding this practice?

A. Hunting will keep the duck population from increasing unchecked and limit growth.
B. The removal of mammals such as foxes and skunks will disrupt other areas of the food chain, such as the population of mice.
C. The duck population will have greater nesting success as a result of reduced predatory concerns.
D. Other waterfowl will enjoy the benefits of less predation.

10. On which of the following conclusions would Scientists A and B agree?

A. Human intervention in natural ecosystems is a necessary step to protect populations.
B. Caution should be taken when creating an ecological situation that favors a single species.
C. Humans can make a change involving a single species with little or no effect on other species in the area.
D. The Kaibab Plateau does not offer any lessons applicable to modern-day issues in ecology.