Question 1

Suppose you were examining whether a synthetic chemical reduced the growth rate of mice. Which action would you take to ensure a controlled experiment?

Accepted Answer

A)  Allow some mice to roam between cages, while having others remained confined to a single cage. 
B)  Exclude one group of mice from exposure to the chemical, but otherwise treat all of the mice in the same manner. 
C)  Compare a natural population of mice exposed to the chemical to a natural population not exposed to the chemical. 
D)  Use computer programs to analyze the results from all treatment groups.

Question 2

Refer to the figures.
 The figures are 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 to Ribeiroia parasites. The tadpoles were then examined for (A) numbers of eosinophils and (B) numbers of Ribeiroia cysts. Error bars show one SD of the mean. Compared with the control group, the frogs exposed to low concentrations of pesticides had about how many times as many parasite cysts?

Accepted Answer

A)  1.5 
B)  3 
C)  4.5 
D)  10

Question 3

Refer to the table.
 The table represents the result of a survey of 39 lakes, some with and some without introduced rainbow or brook trout. The values are averages of the number of frogs present along a 10-meter piece of shoreline in lakes with and without trout. Given these results, one can conclude that

Accepted Answer

A)  introducing trout into a lake seriously depletes the number of frogs present. 
B)  introducing trout into a lake has little or no effect on the number of frogs present. 
C)  introduced rainbow trout decrease frog populations but introduced brook trout do not. 
D)  introduced brook trout decrease frog populations but introduced rainbow trout do not.

Question 4

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

Accepted Answer

A)  70. 
B)  90. 
C)  110. 
D)  180.

Question 5

Which statement is not likely to be true within an ecological community?

Accepted Answer

A)  Organisms have unlimited resources. 
B)  Environmental conditions change over time. 
C)  Environmental conditions change from one place to another. 
D)  Species evolve over time.

Question 6

What is the current consensus view regarding the primary cause of amphibian deformities and declines?

Accepted Answer

A)  The primary cause is habitat loss. 
B)  The primary cause is parasites and diseases. 
C)  The primary cause is global warming. 
D)  There is no current consensus as more research is needed.

Question 7

Biologists find that worms treated with a hormone live 1.3 days longer than untreated worms. To assess whether these differences are significant, the biologists would most likely use which aspect of the scientific process?

Accepted Answer

A)  A control group 
B)  Replication 
C)  Mathematical modeling 
D)  Statistical analysis

Question 8

A rare, highly endangered bird species lives in a very remote area of the Amazonian rainforest. Almost nothing is currently known about this species' diet, behavior, life-span, breeding system, or its interactions with other species. Ecological research can be conducted at five major levels or scales (note that one has already been entered into the table). Complete the table, listing the four other potential levels of ecological study in order from the lowest to the highest level. For each level, list one potential research question that could be asked in a study of the endangered bird species.

Accepted Answer

The answer of A rare, highly endangered bird species lives...

Question 9

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)

Accepted Answer

A)  biosphere. 
B)  community. 
C)  ecosystem. 
D)  population.

Question 10

Biologists find that tomato plants treated with an insecticide produce 2.2% more tomatoes compared to untreated plants. To assess whether these differences are significant, the biologists would most likely use

Accepted Answer

A)  a control group. 
B)  statistical analysis. 
C)  replication. 
D)  mathematical modeling.

Question 11

Which quality is a biotic feature of the environment?

Accepted Answer

A)  The density of consumers 
B)  The average minimum temperature at night 
C)  The number of days during which at least 1 mm of rain falls 
D)  The pH of the soils

Question 12

Refer to the figure.
 
-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?

Accepted Answer

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.

Question 13

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

Accepted Answer

A)  replicating each treatment, including the control. 
B)  assigning treatments to subjects or plots methodically. 
C)  never performing the same experiment twice, but trying instead to improve each experiment. 
D)  carefully setting up experiments so that the results are identical and do not need to be statistically analyzed to prove the result.

Question 14

Refer to the figure.
 The figure represents an ecological study done by Carson and Root to study how herbivorous insects affected a plant community. Based on the figure, what type of study were Carson and Root most likely performing?

Accepted Answer

A)  A controlled field experiment 
B)  An uncontrolled field experiment 
C)  A laboratory experiment 
D)  An observational study

Question 15

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

Accepted Answer

A)  Is a predator species maintaining species diversity by selectively preying on the most abundant prey species? 
B)  How much nitrogen is being taken up by organisms in a given place? 
C)  How does temperature affect survivorship of marmots? 
D)  How do features of the landscape affect the movement of bears?

Question 16

A team of researchers is investigating the effects of fertilizer on the growth of forest trees. They use an old Christmas tree plantation with pine trees of the same species and age, and divide a section of the plantation into 60 plots. They separate the plots into two groups of 30. They apply high fertilizer levels to the group to the east of the plantation and low fertilizer levels to the western group. They set up the experiment to run for ten years and measure growth of all trees at the end of each year. Discuss the validity of the experimental design, concentrating on the formation of treatment groups and the use of controls. Based on this design, would the researchers be able to draw valid conclusions about the effect of fertilizer on tree growth rates? Why or why not?

Accepted Answer

The answer of A team of researchers is investigating the...

Question 17

A team of researchers is investigating the effects of fertilizer on the growth of forest trees. They use an old Christmas tree plantation with pine trees of the same species and age, and divide a section of the plantation into 4,000 plots, with each plot measuring 10 cm F1F1F1S1*F1F1F10 10 cm. They separate the plots into two groups of 2,000 and apply different amounts of fertilizer to the two groups. They collect data on tree growth in each plot for 12 hours and quantify the growth rates with high and low fertilizer applications. Discuss the validity of this design, concentrating on possible spatial and temporal flaws. Based on this experimental design, would the researchers be able to draw valid conclusions about the effect of fertilizer on tree growth rates? Why or why not? Consider the spatial and temporal scales of the design.

Accepted Answer

The answer of A team of researchers is investigating the...

Question 18

How do connections in nature lead to unanticipated side effects in the case of amphibian deformities?

Accepted Answer

A)  Increased pollution levels decrease predation, which allows even deformed frogs to survive and reproduce. 
B)  Increased nutrients in ponds stimulate algal growth and provide the snails with a more abundant food source, which also increases the number of Ribeiroia. 
C)  The increased pollution kills off the frogs' prey and makes it more difficult for them to survive. 
D)  Higher levels of pesticides increase the number of eosinophils in frogs.

Question 19

A plant species has two different varieties, the characteristics of which are heritable. One grows very quickly to a large size, while the other grows slowly and remains small. The large plants produce 500 seeds when they reproduce; 20 of those seeds sprout and survive to become large adult plants. The small plants produce 100 seeds; 40 of those seeds sprout and survive to become small adult plants. Which variety is more likely to be better adapted to its environment?

Accepted Answer

A)  The small plant variety is better adapted. 
B)  The large plant variety is better adapted. 
C)  The two varieties are equally well adapted. 
D)  There is not enough information to decide.

Question 20

An ecologist wants to study a large forest ecosystem which was last studied more than 50 years ago. She hopes to document the changes that have occurred in plant species composition, in light of recent global warming. She will probably begin her study using which method?

Accepted Answer

A)  Field observations 
B)  Field experiments 
C)  Controlled laboratory experiments 
D)  Quantitative mathematical models

Exam 1: The Web of Life