Question 1

If a bird eats a monarch butterfly,the bird will vomit.Monarchs are brightly colored.This example demonstrates ________ coloration.

Accepted Answer

The answer of If a bird eats a monarch butterfly,the...

Question 2

Which of the following patterns represents the outcome of a parasitic relationship?

Accepted Answer

A)  +/- 
B)  +/+ 
C)  o/+ 
D)  -/-

Question 3

Once a mature community develops,is it likely to remain that way indefinitely?

Accepted Answer

A)  No; over long-term time scales, climate change will probably occur, causing the community to eventually change. 
B)  No; once a climax community develops, the lack of biotic variability eventually degrades the habitat. 
C)  Yes; once a climax community develops, it will always remain undisturbed. 
D)  Yes; climax communities become so stable that they prevent disturbances from occurring.

Question 4

Parasites,and the disease they cause,represent a distinctive type of exploitation because

Accepted Answer

A)  of the high mortality rates associated with infection. 
B)  parasites affect only specific portions of the host. 
C)  of the chronic and progressive debilitation of the host. 
D)  parasites represent the only species interaction where the symbiont lives on or in the host organism.

Question 5

Some species of warblers partition their niche by foraging in different parts of the same tree,although all birds eat the same species of insects and spiders.What mechanism has natural selection used to produce this interaction?

Accepted Answer

A)  character displacement 
B)  behavioral modification 
C)  directional selection 
D)  competitive exclusion

Question 6

Which of the following can occur when the climate of an area changes?

Accepted Answer

A)  Natural selection usually causes the community to adapt and survive the change with little visible effect. 
B)  That area becomes uninhabitable to all species and is abandoned. 
C)  That community may relocate to an area with a climate similar to that of the original location. 
D)  Continental drift restores communities to climates similar to those from which the communities came.

Question 7

A species can participate in several symbiotic relationships simultaneously; for example,Scotch broom,an invasive shrub,competes with native vegetation for soil nutrients and maintains a mutualistic relationship with root bacteria.

Accepted Answer

A) True 
 B)False

Question 8

As shown in the following graph,selected intertidal communities along the Washington coast changed when the sea star Pisaster ochraceus was removed.After 10 years,how did those communities compare to control communities?

Accepted Answer

A)  The communities were statistically indistinguishable from one another. 
B)  Without sea stars, the total number of species declined. 
C)  Other predatory sea stars replaced Pisaster. 
D)  Some populations declined, but species diversity was unaffected.

Question 9

The general process by which species in a community are replaced over time is called ________.

Accepted Answer

The answer of The general process by which species in...

Question 10

Pisaster ochraceus,the common Pacific Northwest sea star,is contending with an apparently new disease termed sea star wasting syndrome,which threatens this species with possible extinction.What community changes can be expected if the sea star population is reduced to low levels or disappears entirely?

Accepted Answer

A)  The various sea star predators, such as the California mussel, will experience population declines proportional to the loss of prey; eventually, the diversity of the community will decline. 
B)  Other mussel predators, currently suppressed by exploitation competition, will increase; the diversity of the community will remain about the same. 
C)  Algae and other photosynthesizers will use the vacant space left by the sea stars and increase the food resources; the diversity of the community will increase. 
D)  Mussels will increase and compete with other community members for space; eventually, the diversity of the community will decline.

Question 11

Due to competition,forms of competing species may evolve to become more different from each other over time.This change is known as character ________.

Accepted Answer

The answer of Due to competition,forms of competing species may...

Question 12

Which of the following experiments would help to identify a keystone species?

Accepted Answer

A)  introduce more of the suspected species into the area and observe the effects on other community members 
B)  remove the suspected species from the area and observe the effects on other community members 
C)  introduce an invasive species related to the suspected species into the area and observe the effects on the suspected species 
D)  introduce additional individuals of the suspected species' food source into the area and observe the effects on community members

Question 13

Human cells contain mitochondria,which are responsible for processing the energy needed by our cells.Remember that the ancestors of mitochondria may once have been free-living prokaryotes.If mitochondria were still considered separate organisms within human cells,which of the following would best describe the relationship with them?

Accepted Answer

A)  parasitic 
B)  mutualistic 
C)  competitive 
D)  pathogenic

Question 14

Herbivores interact exploitatively with the plants they consume; do they simultaneously participate in any other relationships within their communities?

Accepted Answer

A)  Yes: an herbivore will have mutualistic relationships with intestinal bacteria and an exploitative relationship with its predators. 
B)  No: community relationships always have costs, so reducing them increases an organism's fitness. 
C)  No: only a single type of interaction can occur at a time, although herbivores can participate in several exploitative relationships at once. 
D)  Yes: each of the plant species eaten needs to be considered a separate interaction.

Question 15

Examine the following graph; what best describes the cycling that each population experiences?

Accepted Answer

A)  Lynx populations decrease in size when hare populations increase in size; hares are the superior competitors. 
B)  Lynx populations increase in size when hare populations decrease in size; lynx are the superior competitors. 
C)  Lynx populations decrease in size when hare populations decrease in size; lynx are exploiting the hare population. 
D)  The increase and decrease of each species is driven by oscillating density-independent factors, but since they share the same habitat, the cycles coincide.

Question 16

During exploitation,consumer organisms never cause their prey to become extinct.

Accepted Answer

A) True 
 B)False

Question 17

Which of the following statements about competition is FALSE?

Accepted Answer

A)  It can limit the distribution of a species. 
B)  It can limit the abundance of a species. 
C)  It can increase the differences between species. 
D)  It can make two species become more alike.

Question 18

The original colonizing organisms in Hawaii came from other localities but currently show relatively little resemblance to these ancestors; why are the organisms that now live on Hawaii so different?

Accepted Answer

A)  Hawaii is a relatively young landmass, so evolution continues there, although it has ceased in most other places on Earth. 
B)  The organisms that live on Hawaii do not have predators, which allows them to evolve into a greater variety of life forms. 
C)  Through time, random evolutionary change led to speciation and produced the unique Hawaiian organisms observed today. 
D)  Community interactions are the most influential force in the evolution of organisms; the communities on Hawaii were different from those of the initial colonists.

Question 19

Coevolution often occurs when natural selection produces evolutionary change in predator and prey populations; a good example is

Accepted Answer

A)  the mottled and spotted coloration of newborn fawns. 
B)  the speed capacities of the cheetah and Thompson's gazelle. 
C)  the migration of the monarch butterfly to Mexico during the winter. 
D)  the colonization of the snout of the gray whale by several species of barnacles.

Question 20

The following figure illustrates how,although pines first established themselves as the dominant tree in the Lake Michigan sand dune community,black oaks ultimately became the dominant species.  What best explains the gradual reduction of the pine?

Accepted Answer

A)  Oaks trap sand, causing the dune to level out; pines can only survive in the low, protected areas between the dunes. 
B)  Pine needles and the shade from existing pines improve the soil composition and moisture, allowing oaks to become established and preventing new pines from surviving. 
C)  Pines replace the grasses, but this destabilizes the dune and increases the amount of moving sand; the loss of pines is not related to the presence of the oaks. 
D)  Actually, oak seeds were always present in the sand; they simply require more time to germinate.

Exam 23: Ecological Communities