Question 1

Suppose you are wanting to study a tropical rainforest community. You choose to use a guild subset to study this community. Which of the following would be appropriate as this subset?

Accepted Answer

A)  All bird species in the rainforest 
B)  All nitrogen fixing plants in the rainforest 
C)  All granivores in the rainforest 
D)  All canopy trees in the rainforest

Question 2

The studies by Power and colleagues of northern California river ecosystems demonstrated

Accepted Answer

A)  that the strengths of species interactions can vary depending on the environmental context. 
B)  the importance of trophic facilitation. 
C)  that species diversity estimates can vary depending on the sampling effort. 
D)  that species can shift from foundation species to ecosystem engineers and back again depending on the environmental conditions.

Question 3

Refer to the table.
Table 3: Species Abundance in Different Communities
  Suppose you are researching an ecological community in a new study area. You divide your study area into quadrats and sample one quadrat a day to determine the species that occupy the area and how many individuals of these species are present. Assume that by the end of your sampling efforts, you have identified all of the species that occur in the study area. Assume that each quadrat sample now reflects a separate community. Focus on samples in quadrats 5, 10, and 12, which will now be referred to as community 5, community 10, and community 12, respectively. Refer to abundances of species A-H shown in Table 3 for each of the three communities and use the data to determine the proportions of species present in different communities to answer the following questions:
a) Quantify the proportion of species present in a new table (this will be referred to as Table 4).
b) Use the data from Table 4 to determine the abundance rank of each species, where a rank of 1 is the most abundant species. Create a new table (this will be referred to as Table 5) showing this data.
c) Based on the proportional abundance and abundance rank of each species use the data in Tables 4 and 5 to graph the proportional abundance of each species as a function of abundance rank for each community. Graph your data as a line graph (this will be referred to as Figure 3).

Accepted Answer

The answer of Refer to the table.
Table 3: Species Abundance...

Question 4

Ecologists are concerned about the establishment of invasive species in new areas because invasive species

Accepted Answer

A)  can have large ecological effects in their new communities. 
B)  that become established are easy to control. 
C)  are often toxic. 
D)  always cause a decline in biological diversity of the communities they invade.

Question 5

Refer to the figure.

- Which species in the figure is an omnivore?

Accepted Answer

A)  Species A 
B)  Species B 
C)  Species C 
D)  Species D

Question 6

Cougars prey on both white-tailed deer and mule deer. Because of their shared predator, each deer's species abundance is affected by the presence of the other deer species. The white-tailed and mule deer are engaged in a(n)

Accepted Answer

A)  direct interaction. 
B)  indirect interaction. 
C)  trophic facilitation. 
D)  predator-prey relationship.

Question 7

The lowest possible value of the Shannon index is _______. Low values indicate _______ species diversity.

Accepted Answer

A)  -1; low 
B)  0; low 
C)  0; high 
D)  1; low

Question 8

Which statement about the "killer alga," Caulerpa taxifolia, is false?

Accepted Answer

A)  It was unintentionally released into the Mediterranean by the Oceanographic Museum of Monaco. 
B)  Its invasive range extends at least as far as Spain on the west and Croatia on the east. 
C)  It is toxic to humans and other mammals. 
D)  It has evolved cold resistance.

Question 9

Refer to the table.
Table 10
  Suppose you are researching an ecological community in a new study area. You divide your study area into quadrats and sample one quadrat a day to determine the species that occupy the area and how many individuals of these species are present. Assume that by the end of your sampling efforts, you have identified all of the species that occur in the study area. You collect additional information on how biomass is transferred through your study system by determining the dietary components of each species during year 12 of your study. Table 10 shows the numbers of individuals that each other individual consumed during year 12. To read the data table, start at a species in column 1, read to the right across that row to find the number of individuals consumed, then read up to determine the species that it consumed. For example, species A consumed 0 individuals of species B (data cell outlined in bold). Refer to the data in Table 10 to understand the structure of the food web in the community in year 12.Answer the following questions:
a) Determine the composition of each species' diets and create a new table (this will be referred to as Table 11) with this data.
b) Create a food web for this system (this will be referred to as Figure 5).
c) Which species is(are) primary producer(s)?
d) Which species is(are) primary consumer(s)?
e) Which species is an omnivore?

Accepted Answer

The answer of Refer to the table.
Table 10
  Suppose...

Question 10

Refer to the table and the figure.
Table 1
  Figure 2
  Suppose you are researching an ecological community in a new study area. You divide your study area into quadrats and sample one quadrat a day to determine the species that occupy the area and how many individuals of these species are present. Assume that by the end of your sampling efforts, you have identified all of the species that occur in the study area. Suppose that in addition to finding individuals and identifying species, you also collect information on abiotic factors and environmental conditions in the study area. Figure 2 shows how abiotic factors vary across the quadrats sampled. Based on your samples of the numbers of individuals of each species that occur in these quadrats (Table 1), which species is most affected by quadrat-level differences in soil water content? Based on both Table 1 and Figure 2, how would you define communities and determine the number of communities in your study area? How might this information influence how you categorize your quadrats into communities?

Accepted Answer

The answer of Refer to the table and the figure.
Table...

Question 11

Which technique was used to determine the source of the alga Caulerpa taxifolia that invaded the coast of California?

Accepted Answer

A)  Fluorescent dyes 
B)  Electron microscopy 
C)  Analysis of DNA sequences 
D)  Magnetic resonance imaging

Exam 16: The Nature of Communities