ecology chapter 19 last exam

What role does disturbance play in the recently discovered mechanism of pond succession that isn't found in the classical mechanism of succession? A) Droughts lower water levels so that plants can colonize lake sediments. B) Rushing water scours the bottom of the lakes, allowing diatoms to colonize. C) Glaciers scour the land, leaving depressions that can fill up with melting water. D) Peat fires remove the vegetation, allowing secondary succession to proceed.

A) Droughts lower water levels so that plants can colonize lake sediments.

Why are there no spruces in the early seral stages of succession at Glacier Bay? A) Spruce seeds are not likely to disperse to the pioneer and low-shrub stages. B) Spruce seedlings are inhibited by the presence of low shrubs. C) Spruce seedlings are not tolerant to the environmental fluctuations in the pioneer stage. D) There are few alder trees in the early seral stages to facilitate spruce establishment.

A) Spruce seeds are not likely to disperse to the pioneer and low-shrub stages.

(Figure 19.11) Given the results in the figure, what might prevent a tree with large seeds, like a chestnut, from establishing in a forest with high densities of sweet birch seeds, an early-succession species? A) The sweet birch seeds would germinate and grow faster, crowding out the chestnut saplings. B) A chestnut seed would never be transported a large distance to the sweet birch forest. C) Sweet birch seedlings exude chemicals that block the germination of chestnut seeds. D) Chestnut seeds, being large, are more likely to be attacked by insects than sweet birch seeds.

A) The sweet birch seeds would germinate and grow faster, crowding out the chestnut saplings.

Which of the following is a pioneer species? A) annual plants with small, light seeds B) plants with large, heavy seeds C) animals that stay affixed to a substrate, like sea anemones D) animals that tend to stay very close to where they were born

A) annual plants with small, light seeds

How could you tell for certain if a plant lived 2000 years ago in a pond sediment sample? A) carbon dating of pollen B) tree rings C) construction of a pond followed by direct observation. D) observation of a chronosequence near the pond

A) carbon dating of pollen

Experimental removal of a single species in a succession would: A) help determine whether that species facilitated the growth of a later-succession species. B) usually have very little effect on succession. C) can happen only in the intertidal zones. D) always increase the energy available for climax species.

A) help determine whether that species facilitated the growth of a later-succession species.

Why do plants in early seral stages exhibit high levels of tolerance? A) Early plants cannot inhibit the growth of other plants. B) Early plants must deal with harsh conditions, such as fluctuating temperatures. C) Early plants are poor competitors and thus must tolerate other plants. D) Early plants have small and light seeds that germinate well under shade.

B) Early plants must deal with harsh conditions, such as fluctuating temperatures.

How do herbivores affect the outcome of succession in intertidal zones? A) They alter the abiotic environment with their waste products. B) They forage on particular types of algae, allowing others to dominate. C) They trample algae, allowing sea anemones to colonize. D) They have little effect on the outcome of succession.

B) They forage on particular types of algae, allowing others to dominate.

What are the characteristics of plants found immediately after a drought in a pond? A) They have few large seeds. B) They have low root-to-shoot ratios. C) They are large and have high tolerance to shade. D) They have extremely slow growth rates.

B) They have low root-to-shoot ratios.

Why does stream succession rely less on how fast organisms can move themselves than terrestrial succession? A) Most streams are short. B) Water can carry organisms from less disturbed to more disturbed sites. C) Most stream organisms are algae. D) Succession happens very slowly in streams.

B) Water can carry organisms from less disturbed to more disturbed sites.

(Figure 9.12) In the experiment associated with the figure, acorn barnacles facilitate the growth of algae. If you removed both acorn barnacles and the limpet predators of algae, what would you be likely to observe over time? A) a dense carpet of little brown barnacles only B) a carpet of little brown barnacles followed by algal growth C) no colonization of any organisms D) a dense carpet of algae only

B) a carpet of little brown barnacles followed by algal growth

What kinds of disturbances might change climax communities on the steep slopes of the Rocky Mountains? A) tornados B) avalanches C) snowstorms D) human hunting of bears

B) avalanches

Changes in North American forest climax communities A) never occur. B) can occur but may happen very slowly. C) don't occur unless there is a gap in the canopy. D) don't occur unless there is an environmental gradient.

B) can occur but may happen very slowly.

What is the clearest way to document succession? A) pollen sediments from a pond B) direct observation C) tree rings D) carbon dating of wood

B) direct observation

In the Sonoran desert of Arizona, young saguaro cacti often begin life in the shade of mesquite trees; they usually die if they begin life in out in the open. This is an example of A) tolerance. B) facilitation. C) a disturbance. D) inhibition. E) a gap-maintained climax community.

B) facilitation.

Garlic mustard (Alliaria petiolata) is a common invasive species in the eastern United States. One mechanism that allows it to dominate in some areas is the production of chemicals that interfere with the ability of other plants to gain nutrients through mutualistic fungi. This mechanism is an example of: A) tolerance. B) inhibition. C) the priority effect. D) facilitation.

B) inhibition.

If a legume inhibits the growth of other plants around it by using noxious chemicals, A) the plant will eventually kill itself with the chemicals. B) nitrogen will build up in the soil over time. C) no birds will come to the area to help distribute the legume's seeds. D) the legume's bacteria will die off, killing the plant.

B) nitrogen will build up in the soil over time.

How are floods that remove organic matter on the surface of rocks similar to gaps observed in forests? A) Both scour the landscape clean. B) Both uncover seeds in the soil. C) Both allow early-succession species to colonize. D) Both happen only in climax seral stages.

C) Both allow early-succession species to colonize.

Researchers have recently proposed a new way lake succession can occur. What is one feature of this new model? A) Lake succession is slow and steady. B) Colonization of plants happens from the lakeshore. C) Colonization of plants happens from the sediments at the lake bottom. D) The production of a peat layer is not necessary in lake succession.

C) Colonization of plants happens from the sediments at the lake bottom.

Why might a forest contain both climax tree species and a few early-succession species? A) Grazers ate most of the grass species in the area. B) Legumes have not established everywhere in the forest. C) Disturbances have produced gaps of intense sunlight. D) Fire has removed most of the understory species.

C) Disturbances have produced gaps of intense sunlight.

Why is tolerance a mechanism that can be found in both early and late seral stages? A) Both early and late seral species need to be tolerant to low levels of moisture. B) Both early and late seral species require high temperatures to germinate. C) Early seral species need tolerance of stressful environments, while late seral species need tolerance of deep shade. D) Early seral species are tolerant to insects and late seral species are tolerant to fire.

C) Early seral species need tolerance of stressful environments, while late seral species need tolerance of deep shade.

In some areas of the western United States pines are an important part of the climax community. Fires occur at regular intervals in these areas. How could fire maintain these pine populations? A) Fires allow pioneer species like annual grasses to colonize. B) Fires cause gaps in the canopy that allow early-succession species to thrive. C) Fires kill understory species, allowing pine seedlings to thrive. D) Fires make it easier for legumes to colonize, increasing soil nitrogen

C) Fires kill understory species, allowing pine seedlings to thrive.

Can you tell what plant seral state you are in by looking at the bird species in a given area? A) Yes, because bird species are usually associated with a particular seral stage. B) Yes, because each bird species eats only a particular type of plant. C) No, because some bird species are associated with many plant seral stages. D) No, because birds eat a wide variety of insects as well.

C) No, because some bird species are associated with many plant seral stages.

Why does secondary succession occur faster than primary succession? A) Direct observation of secondary succession is easier than for primary succession. B) Lichens are better able to colonize soil than bare rock. C) Soil in secondary sites can contain plant seeds and roots. D) Primary succession areas get too much sunlight for succession to happen quickly.

C) Soil in secondary sites can contain plant seeds and roots.

Why does succession in intertidal communities tend to happen faster than succession after a disturbance in terrestrial communities? A) The ocean has a higher concentration of organisms than soil. B) There are many more disturbances in the intertidal zones than in terrestrial areas. C) The generation time of dominant species in the intertidal zone is shorter than that of the dominant species in terrestrial habitats. D) The generation time of dominant species in terrestrial habitats is shorter than that of the dominant species in the intertidal zone.

C) The generation time of dominant species in the intertidal zone is shorter than that of the dominant species in terrestrial habitats.

Why does the species richness level off? A) There isn't enough energy left in the system to allow for more species. B) There are only five or six species of algae and invertebrates in southern California. C) There isn't enough space on the boulders to accommodate more species. D) The boulders have been exposed to the sun for too long, limiting the colonization ability of algae and invertebrates.

C) There isn't enough space on the boulders to accommodate more species.

What characteristic shared by diatoms and cyanobacteria might make them good colonizers of nutrient-poor habitats? A) They are both extremely tough to eat. B) They are both unicellular. C) They both photosynthesize light to make carbohydrates. D) They both have adaptations that allow them to survive droughts.

C) They both photosynthesize light to make carbohydrates.

A sequence of communities that exist over time at a given location is A) a transient climax community. B) never found without soil or organic material. C) a chronosequence. D) an example of secondary succession. E) always showing the same sequence in intertidal areas.

C) a chronosequence.

During succession, communities A) do not change. B) always have a fixed trajectory to the climax stage. C) are always changing. D) are usually shaped by abiotic factors only.

C) are always changing.

(Figure 19.10) These graphs show that succession is associated with a rapid increase in species richness that slows and levels off over time. How might you explain a graph showing succession with an initial increase in species richness followed by a decline in species richness over time? A) a disturbance such as fire B) facilitation C) inhibition D) tolerance

C) inhibition

If you were assigned the task of starting a plant community that could thrive on Mars, where there is no soil on the surface, which might be good to bring for the initial colonization? A) alders B) pines C) lichens D) low-growing bushes E) cacti

C) lichens

To apply the concept of chronosequence, ecologists assume that: A) most terrestrial communities go through the same seral stages. B) the layers in pond sediments are stacked from youngest at the top to the oldest at the bottom. C) older sites and younger sites have undergone the same disturbances. D) wider tree rings represent periods of rapid population growth.

C) older sites and younger sites have undergone the same disturbances.

Why must oxygen concentrations remain at low levels for pond succession to occur? A) High oxygen levels would cause succession to run too quickly, leaving no climax community. B) High oxygen levels increase the chance of drought in areas around the pond. C) Low oxygen levels allow for easier colonization of plants at the pond edge. D) Low oxygen levels decrease decomposition rates, resulting in peat production.

D) Low oxygen levels decrease decomposition rates, resulting in peat production.

Why might direct observation of succession be easier in intertidal communities than in terrestrial communities? A) It is easier to see all of the organisms in an intertidal area. B) Facilitation happens less easily in terrestrial communities, which makes it more difficult to see transitions among seral stages. C) There are many more organisms in a forest than in an intertidal area. D) Organisms in an intertidal area have shorter generation times than organisms in terrestrial communities.

D) Organisms in an intertidal area have shorter generation times than organisms in terrestrial communities.

(Figure 19.14) If you excluded deer from the forest represented by the graph, what changes in importance would you likely see? A) Sugar maple's importance will increase both in the understory and in the canopy. B) American beech's importance will increase in the understory. C) Tulip poplar's importance will increase in the canopy. D) Tulip poplar's importance will increase in the understory.

D) Tulip poplar's importance will increase in the understory.

Over the course of terrestrial succession, what is the general pattern of species richness? A) a constant increase over time B) an increase followed by an abrupt decline C) no change over time D) an increase that plateaus, followed by a slight decline E) a decline followed by an abrupt increase

D) an increase that plateaus, followed by a slight decline

You observe three beech-maple forests in Indiana that began as ponds. How might you determine whether they all started succession with the same community composition? A) carbon-date the maple and beech trees to see how long they have been living; older trees would suggest a more diverse starting community B) calculate the species diversity of lichens found on the trees C) try growing different types of pioneer species at each site D) sample the soils at each site for pollen and carbon-date them to get an estimate of the species that appeared first at the site

D) sample the soils at each site for pollen and carbon-date them to get an estimate of the species that appeared first at the site

Primary succession A) begins with soil containing organic matter. B) lasts much longer than secondary succession. C) has rarely occurred in terrestrial environments. D) usually begins with lichens and mosses.

D) usually begins with lichens and mosses.

Plants _____ should be used for initial seeding of abandoned strip mines. A) with few large seeds B) that are adapted to fire C) with high tolerance to shade D) with long seed viability E) with high root-to-shoot ratios

D) with long seed viability

The age of pollen grain is determined using a. carbon dating. b. elemental dating. c. chronosequences. d. seral dating.

a. carbon dating.

Grazers can change climax communities because they a. consume palatable plants. b. inhibit plants that are not resistant to trampling. c. alter soil conditions with their waste. d. alter natural predator-prey dynamics.

a. consume palatable plants.

Succession studied at Glacier Bay, Alaska, and on the island of Krakatau, Indonesia, has been done using a. direct observations. b. indirect observations. c. chronosequences. d. pollen.

a. direct observations.

A mechanism of succession in which the presence of one species increases the probability that a second species can become established is a. facilitation. b. tolerance. c. inhibition. d. priority effect.

a. facilitation.

Succession in aquatic environments a. is often faster than succession in terrestrial environments. b. is often slower than succession in terrestrial environments. c. has more seral stages than succession in terrestrial environments. d. never reaches a climax community.

a. is often faster than succession in terrestrial environments.

Terrestrial primary succession begins with a. lichens and mosses. b. grasses and herbs. c. lichens and grasses. d. mosses and grasses.

a. lichens and mosses.

Jaccard's index quantifies a. similarity between communities. b. differences between communities. c. community diversity. d. community species richness.

a. similarity between communities.

A climax community is generally composed of organisms a. that dominate in a given biome. b. that were present throughout succession. c. from surrounding communities. d. that are common.

a. that dominate in a given biome.

Which of the following is an example of a transient climax community? a. vernal pool b. wetland c. bog d. intertidal zone

a. vernal pool

Early-succession species are likely to have a. wind-dispersed seeds. b. high shade tolerance. c. short seed viability. d. large size at maturity

a. wind-dispersed seeds.

When succession was studied at the Duke Forest in the Piedmont region of North Carolina, how many years did it take for the forest to revert to deciduous climax forest from agricultural field? a. 300 years b. 200 years c. 150 years d. 50 years

b. 200 years

Inhibition is a mechanism of succession in which a. the probability that a species can become established depends on the presence of another species. b. the arrival of one species at a site affects the subsequent colonization of other species. c. one species decreases the probability that a second species will become established. d. one species increases the probability that a second species will become established.

c. one species decreases the probability that a second species will become established.

Why were wind- and sea-dispersed seeds the first to colonize and survive on Krakatau? a. The seeds of these plants were more resistant to dry conditions than those of animal-dispersed plants. b. In the early days of colonization, there were no forests to attract animals that could disperse seeds. c. Plants with wind-dispersed seeds were able to survive the volcanic blast better than animal-dispersed plants d. Animal-dispersed plant seeds are more likely to be digested than wind- and sea-dispersed plants.

b. In the early days of colonization, there were no forests to attract animals that could disperse seeds.

Which mechanisms of succession depend on one species arriving at a site before another species? a. inhibition and tolerance b. facilitation and inhibition c. tolerance and facilitation d. inhibition, facilitation, and tolerance

b. facilitation and inhibition

In primary succession of sand dunes, the first species to colonize are a. lichens. b. grasses. c. herbs. d. mosses.

b. grasses.

Electrical companies have discovered that dense shrub thickets, once established, can prevent growth of trees under power lines. Which mechanism of succession are these companies using by planting shrubs under power lines? a. facilitation b. inhibition c. tolerance d. shade tolerance

b. inhibition

Transient climax communities can occur when a site a. undergoes rapid environmental change. b. is frequently disturbed. c. is attacked by a pathogen. d. is colonized by invasive species.

b. is frequently disturbed.

Which type of succession would be expected to be the slowest? a. intertidal b. lake c. stream d. All of these types of succession are equally slow.

b. lake

Late-succession species are likely to have a. wind-dispersed seeds. b. large seeds. c. many seeds. d. fast growth rate.

b. large seeds.

Each stage of community change during succession is called a _____ stage. a. succession b. seral c. serial d. community

b. seral

Which of the following is NOT a trait of a pioneer species? a. many seeds b. shade tolerant c. small seeds d. fast growing

b. shade tolerant

Succession in intertidal communities is rapid because a. the climax community has only a small number of species. b. the generation time of the dominant species is shorter. c. species easily disperse into the disturbed habitat. d. algae have a very rapid growth rate.

b. the generation time of the dominant species is shorter.

Which mechanism of succession is independent of the presence or absence of other species? a. inhibition b. tolerance c. facilitation d. facilitation and tolerance

b. tolerance

A climax community that is not persistent is called a _____ climax community. a. shifting b. transient c. variable d. chaotic

b. transient

When succession was initially observed on the islands of Krakatau, plants with _____ seeds dominated. a. animal-dispersed b. wind-dispersed c. sea-dispersed d. ballistic-dispersed

b. wind-dispersed

Which of the following is TRUE about succession? a. Species richness initially increases with time in aquatic succession. b. Species richness initially increases with time in terrestrial succession. c. Both a and b are true. d. Neither a nor b is true.

c. Both a and b are true.

In deciduous forests of Pennsylvania, the climax community used to be composed of large trees of mostly oak, hickory, and tulip poplar, but over time the composition of the understory changed to sugar maple and beech. What was the cause of this shift? a. The original species were infected by a pathogen. b. Sugar maple and beech were facilitated by the original species. c. Deer browsing caused reductions in species that were not browse tolerant. d. The seedlings of the original species were not shade tolerant.

c. Deer browsing caused reductions in species that were not browse tolerant.

Which is true about terrestrial succession? a. Initial conditions do not affect the trajectory of succession. b. Primary and secondary succession result in different climax communities. c. The sequence of seral stages is variable. d. The sequence of seral stages is linear.

c. The sequence of seral stages is variable.

_____ is a mechanism of succession in which the probability that a species can establish itself depends on its dispersal ability and its ability to persist under the physical conditions of the environment. a. Facilitation b. Inhibition c. Tolerance d. Resilience

c. Tolerance

The last seral stage in the process of succession is called the _____ community. a. apex b. baseline c. climax d. final

c. climax

What causes variation in climax communities over space? a. variation in predators b. shifting biomes c. environmental gradients d. all of the above

c. environmental gradients

Invasion of cheatgrass (Bromus tectorum) in the western North America is maintained by a. occasional hurricanes. b. periodic fires. c. extensive grazing. d. frequent logging.

c. extensive grazing.

In the study of Oregon intertidal communities, little brown barnacles (Chthamalus dalii) are first to colonize disturbed areas. Over time, the community is dominated by the acorn barnacle (Balanus glandula). Which mechanism of succession explains the relationship between the two species of barnacles? a. tolerance b. facilitation c. inhibition d. none of the above

c. inhibition

In fire-maintained climax communities in the southeastern United States, periodic fires a. change soil conditions so they do not favor oaks or broadleaf species. b. cause rapid compensatory growth of burned pines. c. kill oak and other broadleaf species but not pines. d. change water relations to conditions that favor pines.

c. kill oak and other broadleaf species but not pines.

Canopy gaps change local forest composition primarily by increased a. nutrient supply. b. coarse woody debris. c. light. d. soil moisture.

c. light.

Stream succession is rapid because a. disturbed sites receive constant inputs of nutrients via runoff. b. organisms that live in streams have rapid growth rates. c. organisms can move downstream from less disturbed sites. d. disturbances that occur in stream communities are often not severe.

c. organisms can move downstream from less disturbed sites.

When considering the effect of one species on the probability of a second species becoming established, facilitation is_____, inhibition is _____, and tolerance is _____. a. neutral; positive; negative b. positive; neutral; negative c. positive; negative; neutral d. negative; positive; neutral

c. positive; negative; neutral

Succession is change in _____ over time. a. species interactions b. species competition c. species composition d. land use

c. species composition

The receding glacier at Glacier Bay in Alaska has been used to study a. competition. b. predation. c. succession. d. nutrient cycling.

c. succession.

The priority effect occurs when a. the first species to arrive at a site have a greater probability of becoming established than subsequent species. b. the first species to arrive at a site have a lower probability of becoming established than subsequent species. c. the arrival of one species at a site affects the subsequent colonization of other species. d. the arrival of one species at a site improves conditions so there is an increased probability of subsequent species becoming established.

c. the arrival of one species at a site affects the subsequent colonization of other species.

What information about species is needed to calculate Jaccard's index? a. diversity b. growth rate c. those present d. mortality

c. those present

Which of the following is NOT an example of a habitat that could undergo primary succession? a. lava flow b. parking lot c. tree-fall gap d. sand dune

c. tree-fall gap

Which of the following is NOT an example of inhibition? a. A species outcompetes another species. b. A species suppresses other species using allelopathy. c. A species casts deep shade to prevent growth of another species. d. A species acts as a nurse plant and increases water available to other species.

d. A species acts as a nurse plant and increases water available to other species.

When seeds of early- and late-succession species were raised under low light conditions similar to those found in the understory of mature forest, researchers found that species with _____ seeds had _____ seedling survivorship in shade. a. small; high b. small; low c. large; high d. There was no relation between seed size and seedling survivorship.

d. There was no relation between seed size and seedling survivorship.

Indirect observations of succession are often done by using a. chronosequences and seral stages. b. seral stages and climax communities. c. climax communities and pollen. d. chronosequences and pollen.

d. chronosequences and pollen.

In the study of stream succession following a major flood event at Sycamore Creek in Arizona, what was the first organism to recolonize the stream? a. fish b. Cladophora c. cyanobacteria d. diatoms

d. diatoms

Succession is best studied using a. indirect observations. b. chronosequences. c. pollen. d. direct observations.

d. direct observations.

Legumes contain nitrogen-fixing bacteria in their roots that increase soil nitrogen for use by other species. This is an example of a. inhibition. b. tolerance. c. suppression. d. facilitation.

d. facilitation.

One of the traits common in late-succession plant species is a. small seed size. b. low root-to-shoot ratio. c. fast growth rate. d. few seeds.

d. few seeds.

Secondary succession takes place in habitats that _____. a. are initially devoid of plants and organic soil. b. have some plants following disturbance. c. have some plants following disturbance but do not have organic soil. d. have been disturbed and contain no plants but still contain organic soil.

d. have been disturbed and contain no plants but still contain organic soil.

Chaparral vegetation found in southern California is an example of a climax community maintained by a. extensive grazing. b. frequent logging. c. occasional hurricanes. d. periodic fires.

d. periodic fires.

Development of communities in habitats that are initially devoid of plants and organic soil is known as _____ succession. a. climax b. initial c. secondary d. primary

d. primary

Which of the following habitats could NOT undergo secondary succession? a. mud slide b. bare rock c. clear-cut forest d. severely burned forest

d. severely burned forest

A pioneer species is ¬¬_____ species to arrive at a site. a. the final b. the penultimate c. one of the first d. the first

d. the first

Some of the first species to colonize an area following disturbance have to persevere under inhospitable conditions such as disturbed soils, low soil moisture, and altered nutrient levels. This is an example of a. the priority effect. b. facilitation. c. inhibition. d. tolerance.

d. tolerance.