Unit 8 Content Questions 5.D/6.E

Which of the following conclusions is most consistent with the data shown in Figure 2?

The number of days an animal spends in ARD does not significantly affect its time of survival after reintroduction of food.

Beaked whales feed at various depths, but they defecate at the ocean's surface. Nitrogen-rich whale feces deposited in surface waters supply nutrients for algae that are eaten by surface dwelling fish. Which of the following best predicts what would happen if the whale population decreased?

The surface fish populations would decline due to reduced populations of algae.

In anoles, small toe pads are better for gripping irregular surfaces such as the forest floor, and large toe pads are better for gripping smooth surfaces such as leaves. Based on the data in Table 1, if brown anoles are introduced into a forest where green anoles currently live, which of the following predictions about the two species is most likely?

Brown anoles will occupy a different area of the forest from green anoles which will minimize competition.

The human sleep-wake cycle is regulated by melatonin. The synthesis of melatonin is regulated by light exposure (Figure 1). The human body typically develops a sleep-wake rhythm that does not respond quickly to change. Long-term exposure to extended periods of bright light after sunset is most likely to affect a person in which of the following ways?

Melatonin synthesis will be inhibited, and the person will have difficulty sleeping.

The pesticide DDT was widely used in the 1940s as a method of insect control. In the late 1950s the first DDT-resistant mosquitoes were discovered, and eventually DDT-resistant mosquitoes were found globally. When DDT is used now, the development of DDT resistance in mosquito populations occurs in months rather than years. Which of the following best explains the observations concerning DDT resistance in mosquitoes?

Natural selection favors DDT-resistant mosquitoes that are already present in a population when DDT exposure occurs.

Developers have approved a project that will permanently reduce the primary producers' biomass by 50 percent and remove all rabbits and deer. Which of the following is the most likely result at the completion of the project?

The biomass of coyotes will be dramatically reduced.

Mosquitoes are frequently a target of insect control strategies because of their ability to spread disease. One strategy is to introduce guppies, a type of freshwater fish, into areas where mosquitoes are a problem. Guppies can consume large numbers of mosquito larvae, which cuts down on the number of mosquitoes living to adulthood. Researchers assessing the effectiveness of the guppy solution are concerned that the introduction of guppies might cause more problems than it is fixing. Guppies are hardy, tolerant of a wide range of environmental conditions, and fast-reproducing. Which of the following predicts the most likely ecological problem that would occur if guppies are introduced into new areas to control the mosquito population?

The guppies might have no natural predators, which will result in a dramatic increase in the guppy population and an increase in competition for other native species.

Yellow-billed cuckoos typically hatch in midJuly. Emerging cicadas are a primary food source for nesting cuckoos. Which of the following best predicts the effect of wildfires on yellow-billed cuckoo populations?

The yellow-billed cuckoo population will decline because the cicadas will emerge before the hatching season begins.

Based on the data, which of the following is the most likely effect of a period of increased volcanic activity that significantly decreases the amount of sunlight reaching a particular ecosystem for several years?

There will be a decrease in the population sizes of most species and a decrease in the number of trophic levels.

Which of the following is the most likely immediate effect of an increase in runoff containing cadmium on the trophic structure of the river community?

There will be a large decrease in the trout population, resulting in an increase in damselfly nymphs.