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Ecology > final exam > Flashcards

final exam Flashcards

1
Q

All pathogens are parasites

A

true

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2
Q

Which statements about enslaver parasites is false?

A

Only invertebrates have been enslaved by parasites

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3
Q

The fungal parasite Cryphonectria parasitica
is responsible for driving its host, the _______, to near extinction in North America.

A

American chestnut

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4
Q

Which statement best describes the relationship between snow geese and plants in the salt marshes that border the Hudson Bay?

A

At low densities, the geese benefit the plants; at high densities, the geese harm the plants

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5
Q

Which observation led ecologists to conclude that resource limitation is not the only factor driving snowshoe hare cycles?

A

Some declining hare populations do not lack food

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6
Q

A bacterium that lives inside an aphid is always classified as a:

A

symbiont

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7
Q

The graphs are results from a study by Hudson and colleagues on red grouse and their nematode parasite. The graphs show the cycling of six red grouse populations subjected to three treatments: (A) two control populations, (B) two populations treated for nematode parasites in 1989, and (C) two populations treated for parasites in 1989 and 1993. Each of the six grouse populations is designated by a different color. These results show that removal of the parasite

A

reduced the fluctuations of the grouse population

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8
Q

Suppose that rabbits are the only prey and food supply of foxes, and that the predator‒prey interaction follows Lotka‒Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits in the absence of predation is 0.2 per week. The capture efficiency is 0.002, and the efficiency at which rabbit biomass is converted into fox biomass is 0.2. If there are 30 foxes in a population, and 400 rabbits are present, the rate at which prey will be killed is _______ per week

A

24

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9
Q

Which of the following is most likely to prevent or stop an arms race between host and parasite?

A

A trade-off between a hosts survival when parasitized and it’s reproductive success in the absence of parasitism

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10
Q

Which statement about parasitoids is false?

A

Parasitoid larvae remain in the host insect but do not eat it

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11
Q

Suppose that a predatory fish eats only minnows and the predator‒prey interaction follows Lotka‒Volterra dynamics. The intrinsic growth rate of minnows in the absence of predators is 0.2 per month, and the mortality rate of the predatory fish in the absence of minnows is 0.1 per month. The capture efficiency rate is 0.004, and the efficiency at which minnow biomass is converted into predator biomass is 0.25. The minnow population size will increase only if the number of predatory fish is

A

below 50

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12
Q

What do the fungus that causes athletes foot, the tick that spreads Lyme disease, and body lice all have in common?

A

they are ectoparasites

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13
Q

In Huffaker’s studies of an herbivorous mite and it’s mite predator, when predator and prey were in a simple environment,

A

prey and predator populations both increased for awhile, but soon crashed and went extinct

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14
Q

Which of the following should reduce the critical threshold for the spread of disease?

A

increasing the rate at which individuals die

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15
Q

Many species of butterflies are noxious to predators. They also have bright red coloration that indicates to the potential predators that they are unpleasant or even harmful to eat. This is an example of _______ coloration.

A

aposematic

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16
Q

In which way can a parasite change an ecological community?

A

by changing the outcome of species interactions

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17
Q

what is carnivory?

A

a trophic species interaction in which the predator is an animal (carnivore) and the prey is an animal

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18
Q

what is herbivory?

A

A trophic species interaction in which the predator is an animal (herbivore) and the prey is a plant or alga.

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19
Q

what is parasitism?

A

A trophic species interaction in which a predator (parasite) lives and feeds on or in its prey (host) without necessarily killing it

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20
Q

what is predation?

A

A trophic interaction in which an individual of one species, a predator, consumes individuals (or parts of individuals) of another species, its prey

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21
Q

what is compensation?

A

An adaptive growth response of plants to herbivory in which removal of plant tissues stimulates the plant to produce new tissues.

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22
Q

what is symbiosis?

A

A relationship in which two species live in close physical and/or physiological contact with each other

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23
Q

how do tobacco plants respond to herbivory?

A

all of the above

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24
Q

which statement about the study of the invasive Klamath weed and a leaf-feeding beetle is true?

A

a leaf-feeding beetle reduced the density of an invasive weed

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25
Q

What is a carnivore?

A

an animal predator that kills and consumes tissues or fluids of live animals

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26
Q

what is an herbivore?

A

an animal predator that consumes or partially consumes the tissues or internal fluids or living plants or algae

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27
Q

what is a parasite?

A

an organism that lives minor on a host organism and feeds on its tissues or body fluids

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28
Q

what is a parasitoid?

A

am insect that lays one or a few eggs on or in a host organism

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29
Q

the hormone ___ stimulates the release of stored glucose to make it available to the muscles.

A

cortisol

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30
Q

In the Lotka‒Volterra predator‒prey model, the parameter a represents the:

A

capture efficiency of prey by predators

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31
Q

in the simple host-pathogen model, which term describes the rate at which disease is spread successfully?

A

bSl

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32
Q

which statement about malaria and the life cycle of Plasmodium is false?

A

the game producing cells arise from sporozoites

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33
Q

Moths resin on the trunks of trees often resemble the tree bark so that potential predators do not perceive them as prey. this is an example of:

A

crypsis

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34
Q

Zust and colleagues found that

A

both b and c

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35
Q

Huge numbers of adult periodic cicadas emerge simultaneously from pupae at intervals of either 13 or 17 years. This phenomenon is most similar to which of the following?

A

masting

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36
Q

Which statement about predator and prey is true?

A

the body form of a cheetah enables it to have great bursts of speed, improving its likelihood of capturing gazelles and other prey

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37
Q

Tapeworms have a ___, which they use to attach themselves to the insides of the host’s intestine.

A

scolex

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38
Q

The transmission coefficient of the hypothetical disease Dirks fever is 0.8. if the combined death and recovery rate is 0.4, what is the threshold density for dirks fever?

A

0.5

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39
Q

When animals are exposed to chronic stress, the stress response suppresses:

A

all of the above (growth, reproduction, immune response)

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40
Q

A bacterium that causes rash on the spinoff mammals upon infection would be classified as a

A

both a and c (ectoparasite and micro parasite)

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41
Q

Which statement about tuberculosis is false?

A

recent advances in medicine and vaccines have cut the worldwide death rate from TB to less than 10,000 per year

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42
Q

Refer to the diagrams, showing the relationship between the relative proportion of prey type A that is available in an area and the proportion of prey type A in the total diet of three different predators. Which predator shows evidence that it prefers to eat the more common prey?

A

predator 2 only

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43
Q

In the simple host–pathogen model, which term describes the rate at which a susceptible individual encounters an infected individual?

A

Sl

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44
Q

How does the protein transferin assist in defenses against parasites?

A

it removes iron from the blood serum in vertebrate hosts and stores it in intracellular compartments

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45
Q

Thomas Park’s studies of flour beetles and their protozoan parasite best exemplified the principle that

A

parasites can alter the outcomes of competitive interactions between species

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46
Q

All predatory relationships have the potential to reduce the ___ of prey or host organisms.

A

all of the above (growth, survival, reproduction)

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47
Q

According to the basic host–pathogen model, if the combined death and recovery rate from a disease doubles, and the effectiveness of the disease to spread from infected to uninfected individuals remains the same, the threshold density should

A

double

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48
Q

what is an isocline?

A

The set of abundances for which the population growth rate (dN/dt) of one of the species involved in a species interaction is zero

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49
Q

what is the Lotka-Volterra predator-prey model?

A

A modified form of the logistic equation used to model predator-prey interaction cycles

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50
Q

what is warning coloration?

A

A defense against predators in which prey species that contain powerful toxins advertise those toxins with bright coloration; also called aposematic coloration

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51
Q

what is a secondary compound?

A

A chemical compound in plants not used directly in growth, and often used in such functions as defense against herbivores or protection from harmful radiation

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52
Q

what is mimicry?

A

A defense against predators in which prey species resemble less palatable organisms or physical features of their environment, causing potential predators to mistake them for something less desirable to eat

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53
Q

what is induced defense?

A

In plant-herbivore interaction, a defense against herbivory, such as production of a secondary compound, that is stimulated by herbivore attack

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54
Q

what is crypsis?

A

A defense against predators in which prey species have a shape or coloration that provides camouflage and allows them to avoid detection.

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55
Q

The most likely change caused by Vibrio cholerae
in its hosts, which aides its dispersal to new hosts, is

A

diarrhea

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56
Q

which parasite would most likely be found in the human small intestine?

A

the tapeworm Taenia saginata

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57
Q

Suppose that rabbits are the only prey and food supply of foxes, and that the predator‒prey interaction follows Lotka‒Volterra dynamics. The mortality rate of foxes in the absence of rabbits is 0.1 per week, and the intrinsic growth rate of rabbits in the absence of predation is 0.2 per week. The capture efficiency is 0.002, and the efficiency at which rabbit biomass is converted into fox biomass is 0.2. If there are initially 30 foxes and 400 rabbits, the overall rate of change in the rabbit population will be a _______ of _______ per week.

A

gain; 56

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58
Q

If the number of rabbits doubles and the number of foxes also doubles, the number of rabbits that are killed will

A

quadruple

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59
Q

Suppose that a predatory fish eats only minnows and the predator‒prey interaction follows Lotka‒Volterra dynamics. The intrinsic growth rate of minnows in the absence of predators is 0.2 per month, and the mortality rate of the predatory fish in the absence of minnows is 0.1 per month. The capture efficiency rate is 0.004, and the efficiency at which minnow biomass is converted into predator biomass is 0.25. The predatory fish population will increase only if the number of minnows is

A

above 100

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60
Q

Which of the following could not be a hemiparasite?

A

any heterotroph

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61
Q

the secondary compounds that are produced by oaks to reduce herbivory are an example of:

A

herbivory defense

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62
Q

In Huffaker’s studies of an herbivorous mite and its mite predator, when predator and prey were in a heterogeneous environment,

A

predators and prey persisted and exhibited population cycles

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63
Q

what is convolution?

A

the evolution of two interacting species, each in response to selection pressure imposed by the other

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64
Q

what is an ectoparasite?

A

A parasite that lives on the surface of another organism

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65
Q

what is an endoparasite?

A

a parasite that lives inside the body of its host organism

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66
Q

what is a macro parasite?

A

Relatively large parasite species, such as arthropods and worms

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67
Q

what is a micro parasite?

A

Parasite species too small to be seen with the naked eye, such as bacteria, protists, and fungi

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68
Q

what is a pathogen?

A

a parasite that causes disease

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69
Q

what is a symbiont?

A

An organism that lives in or on an organism of another species, referred to as its host; a symbiont is the smaller member of a symbiosis

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70
Q

what is threshold density?

A

The minimum number of individuals susceptible to a disease that must be present in a population for the disease to become established and spread.

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71
Q

which organism is an example of a hemiparasite?

A

mistletoe

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72
Q

In humans, red blood cells that have been infected with the parasite that causes malaria are destroyed mainly in the:

A

spleen

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73
Q

which statement about endoparasites is true?

A

all parasites living in an alimentary canal are endoparasites

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74
Q

how do snowshoe hares change when predators are abundant?

A

they alter their behavior

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75
Q

Which of the following would likely result from a decrease in the density of the golden apple snail in an area that previously had large snail populations?

A

the biomass of aquatic plants would increase

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76
Q

which of the following should recuse the critical threshold for the spread of disease?

A

increasing the rate at which individuals die

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77
Q

The graph shows the relationship between the growth rates (on a log scale) of individual fish and the similarity of the fish to their competitors. Assuming that populations with faster growth rates are more likely to have greater population growth, which principle or concept does the graph support?

A

competition can result in character displacment

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78
Q

if rescue levels become sufficeintly low, the intensity of competition can increase.

A

true

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79
Q

Based on Paine’s studies, what has allowed the sea palm to persist in shoreline areas despite the presence of a superior competitor (Mytilus)?

A

periodic disturbances

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80
Q

what is allelopathy?

A

A mechanism of competition in which individuals of one species release chemicals that harm individuals of other species

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81
Q

what is interference competition?

A

An interaction in which species compete directly by performing antagonistic actions that interfere with the ability of their competitors to use a resource that both require, such as food or space

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82
Q

what is interspecific competition?

A

An interaction in which individuals of different species are harmed by their shared use of a resource that limits their ability to grow, reproduce, or survive (-/- relationship)

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83
Q

what is amensalism?

A

A species interaction in which individuals of one species are harmed while individuals of the other species do not benefit and are not harmed (-/0 relationship)

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84
Q

what is intraspecific competition?

A

An interaction in which individuals of the same species are harmed by their shared use of a resource that limits their ability to grow, reproduce, or survive (-/- relationship)

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85
Q

what is exploitation competition?

A

An interaction in which species compete indirectly through their mutual effects on the availability of a shared resource.

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86
Q

how did Brewer manipulate the level of competition in his experiment on pitcher plants

A

by weeding and clipping noncarnivorous competitor species

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87
Q

what is an explanation for coexistence of species that use the same set of limiting resources?

A

all of the above

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88
Q

the principle of competitive exclusion was first formulated by

A

G.F. Gause

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89
Q

Two species of grasshoppers live in the same area. They both feed on plants, but the presence of one species does not affect either the survival or the reproduction of the other. What type of competition is this?

A

this is not an example of competition

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90
Q

the critical feature determining whether a substance is a resource is whether it

A

is required by an organism and can be used to the point of depletion

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91
Q

Based on the Lotka‒Volterra equations, which statement about carrying capacity and species coexistence is most likely true?

A

species with similar carrying capacities are more likely to coexist than species with different carrying capacities

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92
Q

Two similar rodent species are consistently more different from each other when they occupy the same habitat than when they live separately. What is the most likely explanation for the increased divergence when they live together?

A

both b and c

93
Q

competition for resources is common - though not ubiquitous - in natural communities.

A

true

94
Q

In Brown and Davidson’s study of seed-eating rodents and ants in Arizona, the number of rodents _______ when ants were removed, and the number of ant colonies _______ when rodents were removed.

A

increased; increased

95
Q

the physical environment does not affect the outcome of competition or the distribution of species

A

false

96
Q

what is character displacement?

A

process in which competition causes the phenotypes of competing species to evolve to become more different over time, thereby easing competition

97
Q

what is competitive cooexistence?

A

The ability of two or more species to coexist with one another despite competing for the same limiting resources.

98
Q

what is the competitive exclusion principle?

A

The principle that two species that use a limiting resource in the same way cannot coexist indefinitely.

99
Q

what are fugitive species?

A

A species that can persist in an area only if disturbances occur regularly, and must therefore disperse from one place to another as environmental conditions change

100
Q

what is a fundamental niche?

A

The full set of resources, along with other biotic and abiotic requirements, that are suitable for a species excluding the negative interactions with other species

101
Q

what is a realized niche?

A

The part of a fundamental niche that a species occupies as a result of species interactions.

102
Q

what is resource partioning?

A

The use of limiting resources by different species in a community in different ways

103
Q

what is a resource?

A

A feature of the environment, such as food, water, light, and space, that is required for growth, reproduction, or survival.

104
Q

which of the following was a finding of Connell’s experiments with intertidal bacteria?

A

all of the above

105
Q

Two species of birds feed on berries. The birds are active at different times of the day and do not come into contact with one another. Nonetheless, the presence of one species limits the survival and reproduction of the other. What type of competition is this?

A

exploitation

106
Q

In character displacement, competition causes the phenotypes of competing species to evolve to become different from each other over time, thereby reducing the intensity of competition and allowing resource partitioning.

A

true

107
Q

Which statement about Patterson’s study of the distributions of Tamias chipmunks in the southwestern United States is false?

A

they were manipulative experiments

108
Q

Which statement about Tilman and colleagues’ studies of the diatoms Synedra and Asterionella is true?

A

the species that reduced silica levels the furthest when grown alone drove the other species to extinction

109
Q

Which statement about studies on the importance of competition in nature is true?

A

both b and c

109
Q

Suppose that two species of Darwin’s finches live on the same island and eat seeds, but one species tends to eat larger seeds than the other one does. Based on this observation, we can conclude that these species are engaged in

A

resource partioning

110
Q

which of the following cannot be a resource?

A

pH

111
Q

a population at the zero population growth isocline is

A

stable in size

112
Q

competition is often symmetrical, affecting both competitors equally.

A

false

113
Q

Which of the following was a finding of Tansley’s experiments with bedstraw plants?

A

The species that was restricted to acidic soils excluded the species that was adapted to calcareous soils when grown on acidic soils.

114
Q

if soil salinity affects the growth rate of plants but is not depleted by the plants, salinity is not a

A

resource

115
Q

Based on Paine’s studies, what has allowed the sea palm to persist in shoreline areas despite the presence of a superior competitor (Mytilus)?

A

periodic disturbances

116
Q

which statements about roots and NPP is false?

A

root NPP is more difficult to estimate than above ground NPP because roots turn over more slowly

117
Q

which of the following is responsible for the most NPP produced within river and stream ecosystems?

A

macrophytes in shallow areas

118
Q

Root NPP is more difficult to estimate than aboveground NPP because roots turn over more quickly.

A

true

119
Q

Suppose two agents are introduced into soil: one that results in an increase in nitrification and another that results in an equal addition of denitrification. Compared to the soil before, the combination of equal amounts of nitrification and denitrification in the soil would result in a net increase in

A

nitrous oxide

120
Q

All other things being equal, herbivores generally must consume _______ food than carnivores in order to meet their nutritional needs. The reason is that plant material, per gram of carbon, contains _______ nitrogen than animal material does.

A

more;less

121
Q

Which graph best represents the changes in NPP during succession in the typical forest ecosystem?

A

C

122
Q

Suppose that heterotrophs ingested 1,660 kilograms of plant biomass over a month’s period. Respiration of these heterotrophs was the equivalent of 790 kilograms, and they egested 520 kilograms. What is the net secondary production?

A

350 kilograms

123
Q

Based on Gough’s study and others, which graph shows the most likely relationship between plant species richness and soil acidity?

A

graph a

124
Q

imports of nutrients from rivers and terrestrial ecosystems support production in marine ecosystems.

A

true

125
Q

energy in ecosystems originates with primary production by hetereotrophs

A

false

126
Q

Which graph best illustrates the relationship between temperature and primary productivity and temperature and rates of decomposition?

A

graph d

127
Q

Which of the following is not an advantage of remote sensing technologies over harvesting estimates of NPP?

A

they can provide more accurate estimates

128
Q

how does one estimate the NPP if one knows the NEE?

A

NPP = NEE – heterotrophic respiration

129
Q

Suppose that net secondary production in an ecosystem is only 15% of the total amount of plant material ingested by heterotrophs. If herbivores egest 20% of what they ingest, what percentage of what they ingest goes to heterotroph respiration?

A

65%

130
Q

heterotrophs are categorized by what they eat. a detrivores eats:

A

dead, organic material

131
Q

Variation in terrestrial NPP is associated with variation in the spatial distribution of fossil fuels around the world.

A

false

132
Q

Plant species from resource-poor communities often have low growth responses to fertilization because these plants typically have a

A

low intrinsic growth rate

133
Q

What would be the mean residence time of phosphorus in a pond if the total pool is 1,250 grams and the mean rate of input is 2,500 grams? (Assume that rates of input, output, and the total pool size have remained constant.)

A

6 months

134
Q

According to measurements taken in the 1990s, the levels of inorganic nitrogen in Arctic ecosystems were substantially lower than the amount of nitrogen actually taken up by plants. Which of the following is a possible explanation for this pattern?

A

Arctic sedges can take up organic forms of nitrogen.

135
Q

Which of the following would likely have the greatest proportion of productivity going into its own respiration?

A

a large tree in the Brazilian tropical rainforest

136
Q

Specific nutrients play pivotal roles in the structure of ecosystems and the distribution and abundance of organisms. As such, the movement of some specific nutrients can structure communities.

A

true

137
Q

In some ecosystems, NPP actually decreases at very high levels of precipitation. Which of the following is not a likely reason for such declines in NPP?

A

Respiration of heterotrophs increases at high precipitation levels.

138
Q

how do plats and animals differ in how they take up nutrients?

A

Plants take up simple chemicals, which they synthesize into larger molecules; animals take up larger, more complex molecules.

139
Q

In experiments measuring the NPP of grassland ecosystems over time and at different sites, Lauenroth and Sala discovered that

A

some grasslands have different inherent abilities to increase growth in response to increased precipitation.

140
Q

in which biome would yo most likely see the greatest percentage of NPP devoted to roots?

A

tundra in alaska

141
Q

Suppose that the climates in the graph have been maintained for a long period of time. All else being equal, in which climate regime would you expect soil quality in terms of mineral-derived nutrients to be the lowest?

A

regime d

142
Q

when studying terrestrial ecosystems, ecologists commonly focus on an area that is drained by a single stream, which is called?

A

catchment

143
Q

a large plant that grows in warm, swampy environments and faces substantial herbivory most likely

A

both a and c

144
Q

silt is soil that

A

has larger particles than clay

145
Q

According to measurements by Field and colleagues, the total NPP from terrestrial ecosystems is _______% of the total NPP.

A

50-60

146
Q

The availability of nutrient cations such as Ca2+, K+, and Mg2+ to plants may be insufficient in some soils that have low amounts of _______ particles. These particles have _______ that allow them to hold onto cations and exchange them with the soil solution.

A

clay, weak negative charges

147
Q

Of nitrogen and phosphorus, which is the most limiting nutrient to primary production early in primary succession, and why?

A

Nitrogen, because it takes a long time to accumulate in the soil through decomposition

148
Q

the use of harvest techniques to estimate NPP would be most problematic in ___ because ____.

A

tropical rainforests; tissues that die decompose rapidly

149
Q

which statement about soils on the Colorado plateau is false?

A

humans have had little impact on soil conditions

150
Q

What did John Martin mean when he said “Give me half a tankerload of iron, and I’ll give you an Ice Age”?

A

Iron added to ocean water increases NPP, and that increase would lead to more carbon dioxide being taken up by phytoplankton. That would lead to the removal of carbon dioxide from the atmosphere, thus reducing the greenhouse effect.

151
Q

what is an aerosol?

A

Solid or liquid particles suspended in the atmosphere.

152
Q

What is biogeochemistry?

A

the study of the physical, chemical, and biological factors that influence the movements and transformations of chemical elements

153
Q

what is the biological soil crust?

A

A crust on the soil surface composed of a mix of species of cyanobacteria, lichens, and mosses; also called a biocrust

154
Q

what is a catchment?

A

The area in a terrestrial ecosystem that is drained by a single stream; a common unit of study in terrestrial ecosystem studies; also called a watershed

155
Q

what is cation exchange capacity?

A

A soil’s ability to hold nutrient cations such as Ca2+, K+, and Mg2+ and exchange them with the soil solution, determined by the clay content of the soil

156
Q

what is clay?

A

fine soil particles

157
Q

what are horizons?

A

Layers of soil distinguished by their color, texture, and permeability

158
Q

what is lignin?

A

A structural compound that strengthens plant tissues

159
Q

what is litter?

A

Fresh, undecomposed organic matter on the soil surface

160
Q

what is loess?

A

sediment deposited by the wind

161
Q

what is a nutrient?

A

a chemical element required by an organism for its metabolism and growth

162
Q

Which statement best describes the relationship between mechanical and chemical weathering?

A

Mechanical weathering promotes chemical weathering.

163
Q

the total amount of photosynthesis is referred to as

A

GPP

164
Q

Which of the following is one example of the ways in which Arctic plant communities have avoided competition through resource partitioning?

A

Different Arctic plant species take up nitrogen at different depths of the soil.

165
Q

Highest NPP is usually during intermediate stages of succession when plant diversity and nutrient supply tend to be highest.

A

true

166
Q

Which statement best explains the downward trend that follows the peak of each curve?

A

Soils with over 50% water content have concentrations of oxygen that are too low for optimal rates of decomposition.

167
Q

earthworms contribute to decomposition by

A

breaking up litter into smaller particles, thereby increasing the surface area and allowing for more efficient chemical breakdown.

168
Q

The intrinsic growth rates of different plant species influences spatial variation in NPP and its response to variation in resource availability.

A

true

169
Q

Which statement correctly describes the role of nitrogen fixation in the nutrient cycle?

A

N2 is taken up by certain bacteria that can change it into ammonium, a form that is usable by plants.

170
Q

what is atmospheric deposition?

A

The movement of particulate and dissolved matter from the atmosphere to Earth’s surface by gravity or in precipitation

171
Q

what is chemical weathering?

A

The chemical breakdown of soil minerals leading to the release of soluble forms of nutrients and other elements

172
Q

what is denitrification?

A

A process by which certain bacteria convert nitrate (NO3-) into nitrogen gas (N2) and nitrous oxide (N2O) under hypoxic conditions

173
Q

what is eutrophication?

A

A change in the nutrient status of an ecosystem from nutrient-poor to nutrient-rich; such changes occur naturally in some lakes due to the accumulation of sediments, but they may also be caused by nutrient inputs that result from human activities

174
Q

what is leaching?

A

The vertical movement of dissolved matter and fine mineral particles from upper to lower layers of soil

175
Q

what is mineralization?

A

The chemical conversion of organic matter into inorganic compounds

176
Q

what is occlusion?

A

A process by which soluble phosphorus combines with iron, calcium, and aluminum to form insoluble compounds (secondary minerals) that are unavailable to organisms as nutrients.

177
Q

what is nitrification?

A

A process by which certain chemoautotrophic bacteria, known as nitrifying bacteria, convert ammonia (NH3) and ammonium (NH4+) into nitrate (NO3-) under aerobic conditions

178
Q

what is nitrogen fixation?

A

The process of taking up nitrogen gas (N2) and converting it into chemical forms that are more chemically available to organisms

179
Q

what is weathering?

A

The physical and chemical processes by which rock minerals are broken down, eventually releasing soluble nutrients and other elements

180
Q

what is mechanical weathering?

A

The physical breakdown of rocks into progressively smaller particles without chemical change

181
Q

what is decomposition?

A

The physical and chemical breakdown of detritus by detritivores, leading to the release of nutrients as simple, soluble organic and inorganic compounds that can be taken up by other organisms.

182
Q

which statement best describes theorizer of the nitrogen cycle?

A

Plant proteins are converted to N2 through decomposition; N2
is converted to NH4+ through nitrogen fixation; NH4+ is converted back
to proteins in plants.

183
Q

When leaves change color during senescence,

A

both a and c

184
Q

How does the nutrient cycle of aquatic systems differ from that of terrestrial systems?

A

Inputs of nutrients from outside the ecosystems are more important in aquatic ecosystems.

185
Q

what is eutrophic?

A

Nutrient-rich; characterized by high primary productivity.

186
Q

what is mean residence time?

A

The amount of time an average molecule of an element spends in a pool before leaving it

187
Q

what is mesotrophic?

A

Having a nutrient status that is intermediate between oligotrophic and eutrophic, usually used in reference to lakes

188
Q

what is the nutrient cycle?

A

The cyclic movement of nutrients between organisms and the physical environment

189
Q

what is oligotrophic?

A

Nutrient-poor, characterized by low primary productivity

190
Q

what is a pool?

A

The total amount of a nutrient or other element found within a component of an ecosystem

191
Q

what is sand?

A

The coarsest soil particles (0.05-2 mm)

192
Q

what is silt?

A

Intermediate-sized soil particles, often ranging in size between 0.05 and 0.002 mm

193
Q

what is soil?

A

A mix of mineral particles, detritus, dissolved organic matter, water containing dissolved minerals and gases (the soil solution), and organisms that develops in terrestrial ecosystems

194
Q

what is till?

A

Layers of sediment deposited by glaciers.

195
Q

In the 1950s, anthropogenic eutrophication of Lake Washington was caused by

A

phosphates from wastewater

196
Q

Hilderbrand and colleagues wanted to determine the feeding ecology of the extinct European cave bear to determine whether individuals were herbivorous. To investigate this question, they

A

measured the ratio of carbon and nitrogen isotopes in cave bear bone samples and compared it to the ratios found in other known species whose diets were well known.

197
Q

The nutrient requirements of organisms are pretty much all the same regardless of their physiological. As such, nutrient requirements of autotrophs and heterotrophs are very similar.

A

false

198
Q

Suppose that the net primary productivity of a particular ecosystem is 80 units per year. The respiration rate of primary producers is 30 units per year, and the respiration rate of herbivores is 10 units per year. The gross primary productivity is _______ units per year.

A

110

199
Q

Chemical energy derived from the fixation of carbon by photosynthesis and chemosynthesis is known as _______ production

A

primary

200
Q

In his experiments in lakes in Ontario, Canada, Schindler found evidence for phosphorus limitation of NPP. A massive increase in _______ was responsible for the increase of NPP in response to phosphorus addition.

A

cyanobacteria

201
Q

By means of a process called _______, some bacteria can use forms of _______ as electron donors to take up CO2 and convert it to carbohydrates.

A

chemosynthesis; sulfur

202
Q

Why is there likely to be a higher diversity of plant species in soil derived from limestone than in soil derived from granite?

A

The higher acidity of soil derived from granite lowers the availability of nitrogen and phosphorus to plants

203
Q

All living plant tissues lose carbon via respiration, but not all living plant tissues acquire carbon via photosynthesis.

A

true

204
Q

what is an ecosystem?

A

All the abiotic and biotic components of a system that influence the flow of energy and elements

205
Q

what is gross primary production (GPP)?

A

The amount of energy that autotrophs capture by photosynthesis and chemosynthesis per unit of time

206
Q

what is leaf area index?

A

The area of leaves per unit of ground area (a dimensionless number, since it is an area divided by an area)

207
Q

what is net ecosystem exchange (NEE)?

A

The combined fluxes of CO2 into and out of an ecosystem principally by net primary production and autotrophic and heterotrophic respiration

208
Q

what is net primary production (NPP)?

A

The amount of energy per unit of time that producers capture by photosynthesis and chemosynthesis, minus the amount they use in cellular respiration

209
Q

what is net secondary production?

A

The balance between heterotroph energy gains through ingestion and heterotroph energy losses by cellular respiration and egestion

210
Q

what is primary production?

A

he rate at which chemical energy in an ecosystem is generated by autotrophs, derived from the fixation of carbon during photosynthesis and chemosynthesis

211
Q

what is secondary production?

A

Energy in an ecosystem that is derived from the consumption of organic compounds produced by other organisms

212
Q

what is an autotroph?

A

A organism that converts energy from sunlight or from inorganic chemical compounds in the environment into chemical energy stored in the carbon-carbon bonds of organic compounds

213
Q

what is chemosynthesis?

A

The use of energy from inorganic chemical compounds to fix CO2 and produce carbohydrates using the Calvin cycle

214
Q

what is phtosynthesis?

A

process that uses sunlight to provide the energy needed to take up CO2 and synthesize sugars

215
Q

Suppose that the net secondary production in a community is 530 kilograms. The respiration of heterotrophs is 1,400 kilograms, and the egestion is 350 kilograms. Plant respiration is 2,700 kilograms. How much plant material did the heterotrophs ingest?

A

2,280 kilgrams

216
Q

Which ecosystems have the slowest turnover rates of elements (the greatest mean residence times)?

A

Boreal forests with large nutrient pools and low rates of litter input

217
Q

Which of the following would likely have the greatest proportion of productivity going into its own respiration?

A

A large tree in the Brazilian tropical rainforest

218
Q

Which statement about methane and global warming is false?

A

Methane emissions are caused only by anthropogenic factors

219
Q

Which event would lead to enhanced atmospheric warming?

A

Decreased anthropogenic emissions of SO2

220
Q

Refer to the figure, showing the temperature (in °C, relative to modern temperature) and the concentrations of carbon dioxide (in ppm) and methane (in ppb) over the past 400,000 years. The current concentration of carbon dioxide is 404 ppm (not shown on the figure). Use the data in the figure to determine the highest carbon dioxide concentration levels that occurred over the past 400,000 years. At that point, the concentration of carbon dioxide was about _______% of the current concentration.

A

70‒75

221
Q

Which of the following is not one of the currently documented ecological responses to climate change?

A

Migratory birds in England and North America have been arriving at nest sites later in the season.

222
Q

The largest pool of carbon can be found in

A

sediment and rocks

223
Q

According to the studies of Nemani and colleagues, global NPP _______ during the study period (1982–1999), with the largest increase documented in the _______.

A

increased; tropics

224
Q

Which statement best describes our current understanding of the relationship between CO2 levels and photosynthetic activity?

A

Increases in photosynthesis rates due to increases in CO2 levels are likely to be short-lived for some herbaceous plants, but may be more sustained for forest trees.

225
Q

Between 1880 and 2012, the average annual global surface temperature

A

increased 0.8 degrees C

226
Q

In areas such as Vermont that have a seasonal snowpack, which of the following would likely be the most acidic?

A

the first meltwater of spring

227
Q

what equation is used to determine change in prey population over time?

A

dN/dt=rN - aNP

Ecology (4 decks)

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