Deck 31: The Dynamics of Communities and Ecosystems

Question 1

_______ are primary consumers.

A)Ferns
B)Phytoplankton
C)Lions and tigers
D)Cows and sheep
E)Chemosynthesizers

Answer 1

D

Question 2

Which of the following is not a primary producer?

A)a cyanobacterium
B)a diatom
C)a lichen
D)a chemosynthesizer
E)a caterpillar

Answer 2

E

Question 3

In the undisturbed Hubbard Brook forest, scientists detected:

A)considerable loss of nutrients by leaching.
B)considerable addition of nutrients from dissolving bedrock.
C)considerable inefficiency in conserving minerals.
D)a slight annual gain of nitrogen and potassium.
E)a slight annual gain of calcium.

Answer 3

D

Question 4

The existence of more grass plants than herbivores in a grassland ecosystem is illustrated by a(n):

A)pyramid of energy.
B)pyramid of biomass.
C)pyramid of numbers.
D)pyramid of body size.
E)inverted pyramid of biomass.

Question 5

Which of the following statements about parasites is FALSE?

A)They live on or in another organism.
B)They are always one trophic level above their hosts.
C)An example is a virus.
D)An example is a pathogenic bacterium.
E)They can be autotrophs or heterotrophs.

Question 6

In general, ______ percent of the incident light is incorporated into plant biomass.

A)less than 1
B)5 to 8
C)10 to 20
D)25 to 30
E)35 to 40

Question 7

In general, approximately _____ percent of the energy in one trophic level can be assimilated into the next.

A)1
B)10
C)20
D)50
E)80

Question 8

After all plants in a selected portion of the Hubbard Brook forest were killed, scientists detected a(n):

A)decrease in net calcium loss.
B)decrease in net potassium loss.
C)increase in net nitrogen loss.
D)increase in the amount of nitrate in the soil.
E)increase in the amount of potassium in the soil.

Question 9

The biosphere consists of all the Earth's:

A)populations.
B)communities.
C)species.
D)autotrophs and heterotrophs.
E)ecosystems.

Question 10

Which of the following is not an autotroph?

A)a chemosynthesizer
B)a mushroom
C)an oak tree
D)a green alga
E)a moss

Question 11

_______ would be found at the base of a pyramid of energy.

A)Oak trees
B)Elephants
C)Mushrooms
D)Birds
E)Fish

Question 12

A fungus is both a(n) ______ and a ______.

A)heterotroph; primary producer
B)autotroph; primary consumer
C)heterotroph; secondary consumer
D)heterotroph; decomposer
E)autotroph; decomposer

Question 13

_______ is a fuel formed from wetland biomass that accumulates under standing water.

A)Lignite
B)Natural gas
C)Peat
D)Coal
E)Oil

Question 14

Which of the following statements about nutrient cycling is FALSE?

A)An ecosystem has the property of regulating the cycling of nutrients.
B)An ecosystem is self-sustaining in terms of its nutrient supply.
C)Nutrients are continuously cycled between organisms and the environment.
D)In an ideal nutrient cycle, small amounts of nutrients are lost.
E)In a nutrient cycle, the rate of flow differs among nutrients and habitats.

Question 15

Which of the following statements about an upright pyramid of energy is FALSE?

A)It represents the energy relationships among trophic levels.
B)The total energy of producers is represented at the base of the pyramid.
C)The total energy of consumers is greater than the total energy of producers.
D)The total energy of primary carnivores is greater than the total energy of secondary carnivores.
E)The total energy decreases at successively higher trophic levels.

Question 16

______ includes, by definition, all the organisms in a particular place together with their environment.

A)community
B)ecosystem
C)population
D)species
E)biosphere

Question 17

In an ecosystem, energy flows from:

A)consumers to autotrophs to decomposers.
B)decomposers to consumers to autotrophs.
C)autotrophs to consumers to decomposers.
D)consumers to decomposers to autotrophs.
E)autotrophs to decomposers to consumers.

Question 18

A secondary consumer occupies the _______ trophic level.

A)first
B)second
C)third
D)fourth
E)fifth

Question 19

Competition occurs, by definition, when two individuals living in the same area:

A)belong to the same species.
B)belong to the same population.
C)require the same limiting resource.
D)photosynthesize at the same rates.
E)allocate energy in the same way.

Question 20

A community consists of all the ______ in a particular area.

A)individuals of a single species
B)plants
C)plants and animals
D)organisms
E)organisms and their environment

Question 21

What are tannins?

A)Sex attractants in insects
B)Compounds that make plant proteins indigestible to insects
C)Compounds produced by a plant when it is attacked
D)Fungal substances that detoxify pisatin
E)Elicitors produced by bacteria and fungi

Question 22

In nature, the penicillin produced by Penicillium chrysogenum growing on seeds:

A)inhibits seed germination.
B)inhibits the growth of the fungus.
C)inhibits the growth of bacteria.
D)stimulates seed germination.
E)stimulates the growth of bacteria.

Question 23

Which of the following statements about the role of growth rate in competition is FALSE?

A)Plants with a high growth rate often have an advantage over plants with a low growth rate.
B)Plants with a low growth rate may survive if they are able to photosynthesize at low light intensities.
C)Leaf arrangement, crown shape, and patterns of allocation of energy all affect growth rate.
D)A single combination of traits usually produces a competitor that is best in all environments.
E)Within a single community, different species may coexist because of adaptations to different microenvironments.

Question 24

Mutualism is an interaction between two species in which:

A)one species benefits and the other is harmed.
B)both species benefit.
C)both species are harmed.
D)one species benefits and the other is neither harmed nor helped.
E)one species is harmed and the other is neither harmed nor helped.

Question 25

When the two species are grown together, Lemna polyrhiza is replaced by Lemna gibba because L.gibba outcompetes L.polyrhiza for:

A)light.
B)space.
C)carbon dioxide.
D)oxygen.
E)minerals.

Question 26

An example of interference competition is:

A)bears competing for food.
B)earthworms competing for oxygen.
C)plants competing for water.
D)plants competing for minerals.
E)birds competing for territory.

Question 27

The ants of genus Pseudomyrmex that swarm over a bull's-horn acacia tree:

A)harm the plant.
B)provide the plant with sugar.
C)provide the plant with protein.
D)store the plant's seeds.
E)protect the plant against predators.

Question 28

In allelopathy:

A)the alleles of a bacterium or fungus produce pathogenic effects in a plant.
B)some alleles of a plant are pathogenic to that same plant.
C)chemicals produced by a bacterium inhibit growth of a plant.
D)chemicals produced by a fungus inhibit growth of a plant.
E)chemicals produced by one plant inhibit growth of another plant.

Question 29

After a glacier recedes, _____ are often the first to become established on the bare rock.

A)lichens and mosses
B)lichens and ferns
C)mosses and ferns
D)mosses and grasses
E)grasses and lichens

Question 30

The seeds of a serotinous cone are released by:

A)wind.
B)birds.
C)insects.
D)water.
E)fire.

Question 31

An example of secondary succession is:

A)lichens colonizing bare rock.
B)mosses colonizing lava after a volcanic eruption.
C)shrubs colonizing a weedy field.
D)trees colonizing a grassy meadow.
E)grasses colonizing a moss-covered rock.

Question 32

The transition from sugar pine to white fir forests in California was caused mainly by:

A)volcanic eruptions.
B)frequent earthquakes.
C)logging.
D)reduced numbers of forest fires.
E)reduced numbers of settlers.

Question 33

After the cactus moth was introduced in Australia, what was the effect on the prickly-pear cactus?

A)The cacti were able to flower.
B)The cacti produced toxic chemicals.
C)The cactus population was vastly reduced.
D)The cactus population was completely wiped out.
E)The cacti were more widely available to grazing animals.

Question 34

In the northern Rocky Mountains, seedlings of Engelmann spruce outcompete seedlings of subalpine fir in sunny locations because the spruce:

A)has a lower sensitivity to drought.
B)has a lower growth rate.
C)has a greater longevity.
D)grows to a greater size.
E)has more flexible growth requirements.

Question 35

Which of the following statements about mycorrhizal associations is FALSE?

A)Mycorrhizal fungi grow in or on roots.
B)Mycorrhizal fungi can be species that simply grow near roots.
C)They are found in most vascular plants.
D)They are mutualistic associations.
E)They can be highly specific.

Question 36

According to the principle of competitive exclusion, two species with similar requirements:

A)generally grow to the same height.
B)generally photosynthesize at the same rate.
C)cannot take up water equally well.
D)cannot photosynthesize equally well.
E)cannot coexist indefinitely in the same habitat.

Question 37

______ produced by plants are the most important factors preventing attack by herbivorous insects.

A)Thorns
B)Spines
C)Waxy cuticles
D)Secondary metabolites
E)Leathery leaves

Question 38

In the chalk grasslands of England, what happened to the plants when a viral disease reduced the rabbit population?

A)All the plants died.
B)The average height increased.
C)The average height decreased.
D)Diversity decreased.
E)Diversity increased.

Question 39

When ants of the genus Pseudomyrmex were removed from bull's-horn acacia trees, the trees:

A)usually died.
B)were unaffected.
C)grew taller.
D)lived longer.
E)produced thorns.

Question 40

Strains of the Fusarium fungus produce _______ that counter the production of ______ by pea plants.

A)chromenes; helenanin
B)pisatin; chromenes
C)tannins; thorns
D)pyrethrum; waxy leaves
E)monooxygenases; pisatin

Question 41

Energy is recycled in an ecosystem.

Question 42

All chemosynthesizers are microbial.

Question 43

Competition results when individuals living in the same area require the same limiting resource.

Question 44

All autotrophs obtain their energy from the sun.

Question 45

Secondary metabolites are chemicals produced by plants that deter insect herbivores.

Question 46

An example of biological energy conversion is burning coal for fuel.

Question 47

In the bull's-horn acacia, Beltian bodies provide food for ants of the genus Pseudomyrmex.

Question 48

Herbivores usually occupy the base of a pyramid of energy.

Question 49

An example of a parasitoid is a wasp.

Question 50

An herbivore is a primary consumer; a carnivore is a secondary consumer.

Question 51

An example of mutualism is nitrogen-fixing bacteria growing in the root nodules of legumes.

Question 52

Nonprairie species are prevented by ______ from encroaching on prairie ecosystems.

A)wind
B)fire
C)rainfall
D)herbivores
E)low temperature
True-False Questions

Question 53

An aquatic ecosystem is more likely to have an inverted pyramid of biomass than a terrestrial ecosystem.

Question 54

An example of a community is an oak tree and all the organisms that live in and on it.

Question 55

Many species are members of more than one trophic level.

Question 56

Ecosystems usually have eight or nine trophic levels.

Question 57

Detritivores obtain their food from dead and discarded organic matter.

Question 58

Only a small percentage of vascular plants have mycorrhizal associations.

Question 59

All plants are autotrophs.

Question 60

An example of allelopathy is the inability of weeds to grow near sorghum plants.

Question 61

Higher plants are usually the first to become established on bare rock.

Question 62

The Gaia hypothesis suggests that the biosphere functions as an organismal system.

Question 63

Efforts to prevent forest fires in California resulted in enhanced growth of sugar pines.

Question 64

In response to Gypsy moth attack, defoliated oak trees produce new leaves with higher tannin levels than normal.

Question 65

A windstorm can cause a "gap" but a prairie dog cannot.

Question 66

According to the cooperative model for an ecosystem, herbivores do not do irreparable harm to plants.