Question 1

What once was an open pasture on a long abandoned farm has changed over time,without the direct influence of humans.After the cattle had been removed,shrubs and bushes could be seen dotting the grass-covered hillsides.A few years later,small pine trees and then larger deciduous trees appeared.Now,there are so many trees and shaded regions it is difficult to tell that this was once a field.
-These ecological changes in the abandoned pasture represent

Accepted Answer

The ecological changes in the abandoned pasture represent secondary succession, which is the sequence of changes that happens in an area where an ecosystem had previously existed. In this case, the pasture was previously a grassland ecosystem that was disturbed by humans (the cattle being removed). The changes that occur over time, as new plant species colonize and grow in the area, are characteristic of secondary succession.

Question 2

Crown fires

Accepted Answer

Crown fires can create a mosaic of successional stages in an ecosystem by burning intensely in some areas while leaving others less affected, leading to a variety of habitats that support different species at different successional stages.

Question 3

You visit a region with two-way currents to see where many marine organisms inhabit shallow,nutrient rich waters.You are visiting

Accepted Answer

Estuaries are where freshwater rivers meet the saltwater of the sea, creating a unique ecosystem that provides a nutrient-rich environment for many marine organisms. The mixing of freshwater and saltwater creates two-way currents, making estuaries a great place to observe marine life in shallow waters.

Question 4

Moss invades and establishes itself on bare rock,accumulating the beginnings of soil.After several years,enough soil has become established that grasses begin to grow where there was once bare rock.Without the moss building up soil,the grasses would have had no chance.
-The establishment of the mosses on bare rock and eventual addition of grasses represents

Accepted Answer

This scenario describes primary succession, which is the process of colonization and establishment of plant life in an area that was previously barren or lacking in soil. The bare rock is the starting point, and the mosses are the first pioneering plants to establish themselves and begin building up soil. The later growth of grasses is a sign of further succession and development of the ecosystem over time. This process can eventually lead to the establishment of a climax ecosystem, but the scenario described here is still in the earlier stages of primary succession.

Question 5

The frequency of crown fires will decrease if

Accepted Answer

Allowing smaller forest fires to burn naturally can reduce the build-up of fuel, such as dead wood and underbrush, that can contribute to more intense fires. This can decrease the frequency of larger, more destructive crown fires. The other choices listed either do not contribute to decreasing crown fire frequency or may even increase the risk of crown fires.

Question 6

Walking along a large city park on a hot summer day,you look for a cool resting place and sit down on a large rock under a willow tree,at the quiet edge of a stream.You have searched for and found an example of a

Accepted Answer

The specific location under the willow tree by the stream is likely to have its own microclimate, as it may be cooler and moister than other areas of the park due to factors such as shade and proximity to the water. A microclimate is a small-scale climate within a larger region, and is dependent on a variety of factors such as topography and local vegetation. The other options - biome, landscape, and population - are not as applicable to the specific scenario described.

Question 7

Moss invades and establishes itself on bare rock,accumulating the beginnings of soil.After several years,enough soil has become established that grasses begin to grow where there was once bare rock.Without the moss building up soil,the grasses would have had no chance.
-The mosses changed the environment enough to permit grasses to grow in a process called

Accepted Answer

The process in which the mosses change the environment and make it possible for other types of plants to establish themselves is called facilitation. Therefore, the best choice is B. Sublimation refers to the transformation of a substance from a solid phase directly to a gaseous phase, without passing through an intermediate liquid phase. Regeneration refers to the regrowth or reformation of tissue or a body that has been lost or damaged. Improvisation refers to the act of creating or performing something spontaneously or without preparation. None of these options are relevant to the situation described in the question.

Question 8

Primary productivity of the open oceans is very limited because of

Accepted Answer

The primary productivity of open oceans is mainly limited by the shortage of nutrients. In these vast areas, essential nutrients such as nitrogen, phosphorus, and iron are often in short supply, limiting the growth of phytoplankton, which are the foundation of the marine food web.

Question 9

What once was an open pasture on a long abandoned farm has changed over time,without the direct influence of humans.After the cattle had been removed,shrubs and bushes could be seen dotting the grass-covered hillsides.A few years later,small pine trees and then larger deciduous trees appeared.Now,there are so many trees and shaded regions it is difficult to tell that this was once a field.
-The changes in this field,from grasses to shrubs to trees,represent

Accepted Answer

The changes in the field from grasses to shrubs to trees represent ecological succession, which is the gradual and predictable process of change in the composition of a community of organisms over time. It involves the colonization of new species and the gradual replacement of existing species in a particular area. In this case, the field went through the process of primary succession as it was previously devoid of life.

Question 10

Which biome is characterized by permafrost?

Accepted Answer

Permafrost is a layer of soil, rock or sediment that is frozen for more than two consecutive years. Tundra is the only biome characterized by permafrost, which is a defining feature of this cold and treeless ecosystem found in the high latitudes of the Northern Hemisphere.

Question 11

If fire is suppressed in forests that naturally experience frequent fires,

Accepted Answer

When fire is suppressed in forests that naturally experience frequent fires, the buildup of fuel (such as dead trees and vegetation) increases. This can lead to more intense and destructive crown fires when fire does occur.

Question 12

What once was an open pasture on a long abandoned farm has changed over time,without the direct influence of humans.After the cattle had been removed,shrubs and bushes could be seen dotting the grass-covered hillsides.A few years later,small pine trees and then larger deciduous trees appeared.Now,there are so many trees and shaded regions it is difficult to tell that this was once a field.
-In this wooded region that was once pasture,a mature forest of towering oaks and hickory trees has taken over.However,change is still apparent,as a large patch of young shrubs and small trees are growing where several large trees were toppled by a storm several years ago.Collectively,this wooded region represents

Accepted Answer

The passage describes a series of changes in a plant community over time, from an open pasture to a mature forest. This is an example of secondary succession, which is the process of a plant community changing over time after a disturbance. The climax ecosystem is the final stage of succession, and the passage describes the plant community as being in this stage.

Question 13

Which biome is characterized by frequent fires and rich soils?

Accepted Answer

Grasslands and prairies are characterized by frequent fires, which are necessary for the maintenance of the ecosystem. The fires clear out dead plant material, promote the growth of new plants, and prevent the growth of woody plants which would take over the grasslands. The fires also help to enrich the soil by releasing nutrients from the burned plant material.

Question 14

Which of the following represent ecosystems with high average annual net primary productivity?

Accepted Answer

Algal beds, reefs, swamps, and marshes are all highly productive ecosystems, with high rates of photosynthesis and nutrient cycling. They are able to support diverse communities of plants and animals, and are often important habitats for migratory species. The other options listed have lower average annual net primary productivity.

Question 15

As you paddle along in your canoe,you pass alligators,herons,turtles,and tall marsh grasses on your journey through Everglades National Park.This magnificent ecosystem is one of the most famous examples of

Accepted Answer

The presence of alligators, herons, turtles, and marsh grasses indicate a freshwater ecosystem. The Everglades National Park is known for its freshwater wetlands.

Question 16

As successional changes occur in an ecosystem,new species take advantage of new conditions.Where do these new species come from?

Accepted Answer

New species typically come from surrounding ecosystems that are in different stages of succession, allowing them to colonize and thrive in the newly available conditions.

Question 17

About 10% of a large forest experienced a severe fire that burned all but the largest trees.Soon after the fire,the landowner consulted biologists to ask what should be done to the burned region.The biologists explained that if the landowner does nothing,

Accepted Answer

The biologists explained that the burned region will naturally recover and eventually become forest again. This is because many tree species in forests have the ability to regenerate, and the burned area will provide an open space for new growth. It may take some time, but with patience, the forest will regrow on its own. Option A is incorrect because the biologists did not mention anything about erosion. Option B is incorrect because it is not necessarily true that the same region will catch on fire again. Option D is incorrect because the biologists did not mention anything about invasive species.

Question 18

The natural succession of a small farm pond will tend to

Accepted Answer

Natural succession in a small farm pond leads to an increase in sediment depth due to the accumulation of organic and inorganic materials. This process gradually fills in the pond, making it shallower and more susceptible to freezing solid in the winter.

Question 19

Which biome is characterized by the highest annual rainfalls and primary productivity?

Accepted Answer

Tropical rainforests are known for receiving the highest annual rainfalls, with some areas receiving over 100 inches of rain per year. This consistent rainfall leads to high levels of primary productivity, as vegetation is able to grow and flourish throughout the year. In comparison, temperate deciduous forests and grasslands typically receive less rainfall and have lower levels of productivity, while tropical grasslands may experience seasonal droughts that limit productivity.

Question 20

Compared to an ecosystem with just a single stage of succession,an ecosystem with a variety of successional stages

Accepted Answer

An ecosystem with a variety of successional stages has a greater biodiversity compared to an ecosystem with just a single stage of succession. With the presence of different successional stages, there are more niches available for different species to occupy, leading to greater biodiversity.

Quiz 5: Ecosystems: Energy, Patterns, and Disturbance