Ecology Test 1-3

The figure is based on Johnson’s experiment on the effects of trematode parasites on tadpoles. Suppose that 60 tadpoles are exposed to 32 parasites per tadpole. Based on the results of the figure, about how many tadpoles would you expect to survive to metamorphosis?
a. 12
b. 25
c. 40
d. 58

The figure is based on Kiesecker’s field experiments testing the effects of parasites and pesticides on frogs. Which statement is the most valid interpretation of the results?
a. Exposure to parasites was necessary for the frogs to become deformed.
b. All frogs exposed to parasites were deformed.
c. Exposure to pesticides was necessary for frogs to become deformed.
d. Exposure to pesticides had no effect on the percentage of frogs that became deformed.

The figure is based on studies of the effects of pesticides on the tadpole immune system. In a laboratory experiment, wood frog (Rana sylvatica) tadpoles were exposed to low or high concentrations of a pesticide, and then Ribeiroia parasites. The tadpoles were then examined for (A) numbers of eosinophils and (B) numbers of Ribeiroia cysts. Error bars show one SE of the mean. Which statement is supported by the evidence shown in the figure?
a. Tadpoles exposed to high levels of pesticides had more cysts per tadpole than those exposed to low levels of pesticides.
b. Tadpoles exposed to pesticides had fewer eosinophils than those not exposed to pesticides.
c. The number of cysts per tadpole was similar in the solvent control and low pesticide groups.
d. Pesticides decreased eosinophils more when tadpoles were exposed to high concentrations of pesticides than when they were exposed to low concentrations.

Which statement is least accurate in describing the field of ecology?
a. Ecology involves the scientific study of interactions between organisms and their environment.
b. Ecology is an interdisciplinary field that incorporates concepts from the natural sciences, politics, and ethics.
c. Ecology involves the scientific study of interactions that determine the distribution and abundance of organisms.
d. Ecological research can focus on many scales, from individuals up to biospheres.

Scientists are concerned about the growing problem of dead zones in the Gulf of Mexico, which are caused primarily by fertilizer runoff entering the Mississippi River. Which question related to this topic would most likely be studied by an environmental scientist, as opposed to an ecologist?
a. How does the presence of fertilizers in river water affect fish populations along the river?
b. What is the total amount of fertilizer runoff reaching the Gulf of Mexico per year?
c. What economic incentives might be offered to farmers to encourage them to decrease fertilizer runoff?
d. Which types of algae and bacteria undergo population explosions in the Gulf due to increased nutrient content, and during what times of year do they occur?

Scientist A works in a laboratory, studying the effects of CO2 levels on algae and zooplankton. Scientist B works at a field station studying how changing CO2 levels in the atmosphere affect algae and zooplankton in the ocean. Scientist C works in Washington, D.C., lobbying members of Congress to pass legislation to lower CO2 emissions from cars and power plants. How would these three scientists most likely be classified?
a. Scientists A and B are ecologists; Scientist C is an environmental scientist.
b. Scientist A is an ecologist; Scientists B and C are environmental scientists.
c. Scientists A and B are environmental scientists; Scientist C is an ecologist.
d. All three are environmental scientists.

A group of individuals of a single species of swamp sparrows lives in the Quabbin Reservoir in Massachusetts, and these individuals interact with one another. This is an example of a(n)
a. biosphere.
b. community.
c. ecosystem.
d. population.

Net primary production (NPP) is the amount of
a. heat lost through respiration, minus the energy gained by photosynthesis or other means.
b. energy that producers fix by photosynthesis or other means, minus the amount lost as heat in cellular respiration.
c. energy gained through consumption, minus the amount lost as heat in cellular respiration.
d. energy that producers fix by photosynthesis or other means, minus the amount lost through death of tissue.

In a grassland ecosystem, plants capture 180 units per day of solar energy, and use 70 units per day in respiration. Animals consume about 20 units per day of the plants. The NPP of this system, in units per day, is
a. 70.
b. 90.
c. 110.
d. 180.

The figure represents energy flow and nutrient cycling through the major components of natural ecosystems. Based on the figure, which statement best describes a major difference between nutrient cycling and energy flow?
a. Nutrients flow through producers and consumers but not through the physical environment.
b. Energy flows through producers and consumers but not through the physical environment.
c. Both nutrients and energy are lost as they travel through the ecosystem.
d. Incoming solar radiation plays a limited role in both nutrient cycling and energy flow.

An ecologist is studying the impacts of the aquaculture of a fish species on an estuary. His study involves three experimental setups: 1) A controlled laboratory experiment in which fish are kept in small aquaria, 2) A controlled field experiment in which the fish are kept in large tanks, and 3) A field experiment in the estuary itself, in which the fish are kept in mesh cages so their secretions enter the estuary water. In all cases, the ecologist measures specific chemical factors to determine the fishes’ effect on water quality. Later, he will combine results of all experiments into an aquaculture model. Why might the ecologist choose to use this complex set of experimental setups rather than just choosing one?
a. Each spatial scale provides different types of information, resulting in a more thorough and precise picture of the aquaculture ecosystem’s impacts.
b. Each spatial scale gives one part of the total picture; putting them all together provides complete information on all characteristics of the aquaculture ecosystem.
c. Using several types of experimental designs allows the scientist to compare the different sets of data and decide which one is most accurate.
d. The different experimental setups represent replications of the aquaculture ecosystem; averaging them gives an accurate picture of the total system.

In studies of seed production, why is it important to assign plots of land to either the control group or treatment group at random?
a. It increases the likelihood that the treatment group will show a difference from the control group.
b. It decreases the likelihood that plots receiving a particular treatment share other characteristics that might influence seed production.
c. It increases the likelihood that the study can be scaled up to a higher level.
d. It decreases the likelihood that the results of the study will be challenged.

The figure shows a field set up to do controlled ecological experiments, divided into 112 plots each 5 × 5 meters. Suppose 40 plots are chosen for a study, 20 as controls and 20 as experimental plots. The control plots are left untreated. The 20 experimental plots all receive the same treatment: a specific level of insecticide. These experimental plots represent
a. 20 separate experimental treatments.
b. 20 replications of the same treatment.
c. the minimum number of plots needed for statistical analysis.
d. the number of plots needed to match the control plots.

An ecologist studying ecosystems would be most interested in which question?

Is a predator species maintaining species diversity by selectively preying on the most abundant prey species?

How much nitrogen is being taken up by organisms in a given place?

How does temperature affect survivorship of marmots?

How do features of the landscape affect the movement of bears?

Which sequence represents the correct order of levels of biological organization, from largest to smallest?

Biosphere > ecosystem > population > community

Biosphere > population > ecosystem > community

Biosphere > ecosystem > community > population

Ecosystem > biosphere > community > population

Which quality is a biotic feature of the environment?

The density of consumers

The average minimum temperature at night

The number of days during which at least 1 mm of rain falls

The pH of the soils

Which statement about the relationship between consumers and producers is true?

Consumers obtain energy by eating other organisms; producers obtain energy by decomposing dead matter.

Consumers obtain energy from an external source to produce their own food; producers obtain energy by decomposing dead matter.

Consumers obtain energy by eating other organisms; producers use energy from an external source to produce their own food.

Consumers and producers both obtain energy by eating other organisms; the difference lies in what types of organisms they eat.

Which statement about the movement of energy through ecosystems is true?

Energy can be recycled through consumers and producers.

Energy can move in one direction only and cannot be recycled.

Energy can reverse direction if organisms are allowed to decompose.

Recent technology allows us to recycle the energy in our ecosystem.

Ecologists try to reduce the likelihood that variables that are not under the control of the experimenter will unduly influence the results of an experiment by

replicating each treatment, including the control.

assigning treatments to subjects or plots methodically.

never performing the same experiment twice, but trying instead to improve each experiment.

carefully setting up experiments so that the results are identical and do not need to be statistically analyzed to prove the result.

In equatorial regions, the sun’s rays strike Earth’s surface at a more _______ angle than they do toward the poles. This means that the same amount of energy is spread over a(n) _______ area in equatorial regions than in polar regions.
a. perpendicular; smaller
b. perpendicular; larger
c. acute (less than 90 angle); larger
d. acute (less than 90 angle); smaller

Which statement best explains why atmospheric pressure declines with altitude?
a. As altitude increases, there are fewer air molecules pressing down on a given molecule of air.
b. At higher altitudes, air is cooler and thus does not move around as much as the warmer air at lower altitudes.
c. As altitude increases, air holds less moisture and thus feels lighter.
d. There is more subsidence as altitude increases.

Compared with land at the same latitude, ocean waters tend to be _______ in the winter and _______ in the summer because water has a _______ heat capacity than land has.
a. warmer; colder; higher
b. colder; warmer; lower
c. warmer; warmer; higher
d. colder; colder; lower

The map is of an imaginary planet that is roughly the same as Earth. Like Earth, it is tilted on its axis by about 23, and it rotates around a sun-like star in approximately one year. Which site would mostly likely have the greatest variation in temperature during the year?
a. Site A
b. Site B
c. Site C
d. Site D

The figure illustrates the rain-shadow effect. Which of the following descriptions of what is being illustrated here is correct?
a. The prevailing winds are blowing from the right side of the figure, accumulating moisture as they move up the slope, leaving the air on the right side of the mountain very dry, and then depositing the moisture as precipitation on the left side of the mountain.
b. The prevailing winds are blowing from the left side of the figure, accumulating moisture as they move up the slope, depositing the moisture at the crest of the mountain, and then leaving the air descending the slope on the right side very dry.
c. The prevailing winds are blowing from the left side of the figure, depositing moisture as the air moves up the slope and cools, leaving the air descending the slope on the right side of the figure very dry.
d. The prevailing winds are blowing from the left side of the figure, depositing moisture as the air moves up the slope and warms, leaving the air descending the slope on the right side of the figure very dry.

In which aquatic ecosystems are oxygen concentrations in the water usually highest?
a. Rapidly running rivers
b. Deep lakes
c. Slowly running rivers
d. Deep oceans