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BIOL 215 > Ecological Interactions > Flashcards

Ecological Interactions Flashcards

1
Q

what is a habitat?

A

the physical place where an organism lives

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2
Q

what is a niche?

A

how an organism makes its living

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3
Q

what is competition?

A

occurs when an organism shares one or more resources with one or more other organisms, and the use or consumption by one organism reduces the availability of at least one resource to other organisms

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4
Q

what is a resource?

A

any substance that leads to individual or population growth/decline if the substance is increased/decreased

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5
Q

Liebigs Law of the Minimum

A

population numbers can be regulated by a single resource that has the greatest relative scarcity

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6
Q

was nitrogen determined to be a resource

A

for plants yes but not humans

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7
Q

what did grinnell and cause study?

A

interspecific competiton

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8
Q

what did grinnell and gause do?

A

they gave 2 species of paramecium a fixed amount of bacteria as a food source. when grown separately, they showed sigmodal growth, but when grown together, one species overtook the other

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9
Q

competitive exclusion principle

A

two species with the same niche cannot coexist

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10
Q

T/F: two species with very similar resource requirements can co exist

A

true but uncommon

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11
Q

predation on arctic lemmings by foxes and owls, tree diversity in tropical forests, and the “paradox of plankton” are all example of what?

A

two species with very similar resource requirements co-existing

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12
Q

how can two species with very similar resource requirements co-exist?

A

subtle differences in resource use among species. predators reduce population sizes below carrying capacity allowing other species to coexist

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13
Q

_____ difference switches the competitive ability of two beetle species, allowing them to coexist

A

3.2 degree

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14
Q

wo beetle species occupy nearly the same niche, but thrive at different temperatures. this is an example of ____ _____

A

habitat diversity

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15
Q

evidence for interspecific competition in nature

A
  • habitat shifts in allopatry and sympatry
  • character displacement and resource partitioning
  • habitat differences and resource partitioning
  • alleopathy
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16
Q

two different species of trout living in two different lakes is an example of _____ populations

A

allopatric

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17
Q

two different species of trout living in the same lake is an example of _____ populations

A

sympatric

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18
Q

what is allopatry

A

‘different home’

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19
Q

what is sympatry

A

‘same home’

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20
Q

Character displacement (ecological and reproductive)

A

tendency for 2 species to diverge in form (beak) or behaviour when in sympatry.
-natural selection will favour one of the birds

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21
Q

Increased floral divergence in sympatric monkeyflowers:
sympatric sister species are predicted to have greater _____ in reproductive traits than _____ sister species

A

divergence, allopatric

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22
Q

Galapagos finches’ beak sizes are an example of _____ displacement in _____ populations

A

character, sympatric

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23
Q

Increased floral divergence in sympatric monkeyflowers:
this study is an example of _____…_____

A

reproductive character displacement

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24
Q

similar species living at different heights in the same environment is an indicator of _____ _____

A

past competiton (or niche divergence)

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25
Q

the ghost of competition’s past

A

character displacement often is due to the competition between species in the past

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26
Q

artificial introduction of species into habitats where they previously did not exist frequently leads to the _____ of native species that occupy _____ _____

A

dispalcement, similar habitats

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27
Q

after arrival in a Nevada forest in 1978, 8 starlings displaced 12 species of native nesting birds, primarily through _____ _____ and _____…_____

A

aggressive harassment, direct competition for space

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28
Q

scotch broom introduced from Europe has greatly expanded and is now threatening native _____ _____

A

garry oaks

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29
Q

invasive non-native plant species grow _____ and _____

A

quickly, aggressively

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30
Q

what is allelopathy?

A

chemical competition in animals and plants
- the release of chemicals by one species in order to reduce growth/survivorship of another species

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31
Q

what is an example of allelopathy

A

roots of black walnut tree secrete juglone, highly toxic and kills or injures other plants within 20m radius of trunk

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32
Q

juglone is toxic to

A

herbivorous insects and other plants

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33
Q

salvia

A

produces volatile terpenes. Barren zone around them. With cages seeds germinated even in the presence of terpenes; there is an animal activity sufficient enough to produce this bare zone

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34
Q

what is a habitat

A

the physical place where an organism lives

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35
Q

what is a nice

A

how an organism makes its living

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36
Q

what is elton’s niche

A

the role of a species in a community

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37
Q

what is hutchinson’s niche?

A

all biophysical conditions that characterise the life of a species

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38
Q

what is a fundamental niche?

A

the entire multidimensional space that represents the total range of conditions within which an organism can function without limiting factors

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39
Q

what is a realized niche?

A

the actual multidimensional space that a species can occupy taking into account biotic factors such as predators, competitors and parasites

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40
Q

what equation quantifies niche overlap?

A

d/w

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41
Q

what is d?

A

distance between two species in average resource use

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42
Q

what is w?

A

measure of resource spectrum breadth of a species

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43
Q

given 3 species, what level of co-existence is achieved if d/w is <1?

A

no co-existence

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44
Q

given 3 species, what level of co-existence is achieved if d/w is >3?

A

full co-existence

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45
Q

as different resources come into account, the niche becomes an _____ _____

A

n-dimensional hypervolume

46
Q

what is huchinson’s concept of niche space?

A
  • 2 dimensional (height above ground, size of prey)
  • don’t want it to overlap in height or horizontally
  • niche space becomes a volume
47
Q

what is the equation for Lotka and Volterra’s competition model?

A

dN/dt = rN[(K-N)-αN₂]/K

48
Q

what does Lotka and Volterra’s competition model measure?

A

effect of species 2 on population growth of species 1

49
Q

what is α?

A

competition coefficient

50
Q

competition coefficient

A
  • per capita competitive effect of species 2 on species 1
  • a measure of the inhibitory effect of one individual of species 2 on the population growth of species 1
51
Q

total competitive effect of species 2 on species 1 = ?

A

α*N₂

52
Q

if alpha is 1, then _____ _____ of species 2 equals _____ _____ of species 1

A

one individual, one individual

53
Q

if alpha is 0.1, then _____ _____ of species 2 equals _____ _____ of species 1

A

10 individuals, one individual

54
Q

what is biophagy

A

one organism feeding on another

55
Q

Types of biogaphy

A
  • Carnivory
  • Herbivory-grazing
    ->browsing (eats wood)
  • parasitm and parasitoids (parasitic wasps)
  • pathogens
  • scavengers and detritivores (consumption of dead plant or animal material)
56
Q

what is the main cause of curves in survivorship curves?

A

predation

57
Q

functional response curve (FRC)

A

rate of food consumption and density of prey (i.e. a numerical relationship between number of prey eaten by predators in relation to abundance of prey)

58
Q

which FRC types describe a predator consuming a single prey species?

A

FRC I, and II

59
Q

which FRC types describe a predator consuming multiple prey species?

A

FRC III

60
Q

threshold of security

A

minimum density under which no further predation occurs

61
Q

compensatory predation

A

predator behaviour at low prey densities

62
Q

at low prey densities:

A
  • reduced search efficiency
  • prey switching
  • search image
  • aggregated responses of predators
63
Q

virtually all predators target ___ and _____. there is minimal predation to _____

A

juveniles, post-reproductive adults, reproductive adults

64
Q

why dont predators target reproductive adults?

A

high risk of injury, takes more energy.

65
Q

what happens when they killed a bunch of kingfishers on the salmon study

A

number of smolts getting to the ocean increased (x3) BUT: number of adults returning after 3 years were the same (50)
- supports liebigs law

66
Q

Grouse predation study

A

forest was split in two, predators were removed from one.
- in year one the control forest with predators lost more grouse but in year two there was the same amount of grouse. ( no statistical difference after 2 yrs)

67
Q

effects of wold predation of caribou density:

A

population increases, greatly exceeds carrying capacity and then crashes

68
Q

wolves keep caribou numbers from..

A

exceeding k

69
Q

after wolves were removed, caribou population density temporarily increased from _____ caribou/km^2 to _____ caribou/km^2

A

0.4, 20

70
Q

isle royale study

A
  • lake froze and wolves went to island where moose live
  • when the wolf population dec. there was more homozygosity and diseases
  • needed more wolves to keep the moose from carrying capacity so more wolves were introduced
71
Q

what do wolves in Isle Royale and parasitic wasps have in common?

A

both keep prey population under control

72
Q

parasitoid process

A
  • adult wasp delives 2 stings to the cockroach. First sting causes legs to buckle, 2nd sting in brain, controlling escape reflex
  • leads to burrow, wasp lays egg on cockroach
  • egg hatches and larvae chews into cockroach, eats organs for 8 days
  • weaves cocoon inside cockroach and grows into adult and breaks out
73
Q

what do dingoes and domestic cats have in common?

A

both collapse prey population

74
Q

why are artificial predators so hard on native prey species?

A

no co-evolution

75
Q

dingoes affect the _____ of wild pigs by almost eliminating ____

A

age structure, juveniles

76
Q

when dingoes are absent what age class of wild pigs is most present?

A
  • under 1 year
  • when dingoes present more pigs are in 2-5 range, not many young
77
Q

do predators limit prey density?

A

No: if liebigs law is acting
yes: if carrying capacity has been exceeded
yes: when native prey have no defenses against non-native predators

78
Q

endotherm

A

an animal whose body temperature is regulated by the internal heat the animal produces

79
Q

average biomass ratio of prey to predator endotherms

A

1: 300

80
Q

ratio of biomass of prey to predator ectotherms

A

1:5, 20:100

81
Q

what is the average exploitation rate of prey by each predator species?

A

~5%

82
Q

what is the range of exploitation rate of prey by predator species?

A

5-10%

83
Q

what is the fastest predator exploitation rate?

A

human predators
- exploiting 14x higher than other predators
- because we are targeting reproductive adults

84
Q

what type of prey to natural predators take?

A

juveniles “ biological interest “ , the weak, the post-reproductive

85
Q

exploitation rate of prey per preditor species: commercial fisherman take from ____ to ____%
natural predator take from _____ to _____ %

A

10 - 90% (generally 50%), 0-20%

86
Q

3 factors that make humans “super-predators”

A

competitive dominance
impact on predators
other unique predatory behaviour

87
Q

defenses against predators

A

camo, crypsis, conspicuous
speed, agility, stamina, protean behaviour
autotomy - limb release
armour.. spines

88
Q

what are the 3 stages of hunting/foraging for prey?

A

search, pursuit, capture

89
Q

what will protect prey during the search phase?

A

camouflage, crypsis, warning

90
Q

what will protect prey during the pursuit phase?

A

speed, agility, stamina, protean behaviour

91
Q

what will protect prey during the capture phase?

A

spines, armour, behaviour, autotomy, toxicity

92
Q

what stage of being hunted ends in death?

A

capture

93
Q

what is aposematic

A

warning coloration

94
Q

why does aposematic colouration work

A

predators learn to minimize contact

95
Q

what is mullerian mimicry?

A

many poisonous species develop similar conspicuous colour patterns (mimic each other)

96
Q

what is batesian mimicry?

A

a non-stinging or edible species mimics a stining or poisonous species

97
Q

batesian mimicry:
a hoverfly is the _____
a wasp is the _____

A

mimic, model

98
Q

defoliation

A

to strip a tree, bush, etc of leaves

99
Q

herbivory can reduce growth rate of a plant by up to ____%

A

25%

100
Q

plant structural defenses:
to minimize browsing by large animals, plants grow _____

A

spines

101
Q

effects of herbivory on plants

A
  • loss of competitive ability
  • defoliation
  • go for young leaves, less lignin, more nutrients
  • growth rate of plant reduced by up to 25%
102
Q

plant defenses

A
  1. chemical
  2. structural defences
102
Q

plant chemical defences

A
  • unpleasant odour
  • contact irritation
  • bitter taste
  • neurotoxins
  • proteinase inhibitors
  • growth hormone mimics
  • psychotropic effects
103
Q

unpleasant odour example

A

mustard

104
Q

contact irritation example

A

poison ivy
- contact dermatitis

105
Q

bitter taste example

A

berries when not ripe, tannins - alkaloids

106
Q

neurotoxins

A

dinoflagellates

107
Q

proteinase inhibitors

A

cotton, chickpea, potato
-inhibit the metabolism of these, they don’t get broken down and animal will starve to death

108
Q

growth hormone mimic

A

cat nip
- mimics the moulting hormone if animal eats this, moults too early/late and die

109
Q

psychotropic effects

A

Peyote (mescaline)
- antibrowing to kangaroo rats, flips out when they eat it
Caffeine
- when spiders have caffeine or mescaline, they suck at making webs

110
Q

Animal defenses against plant chemical defenses

A
  1. mixed function oxidase - oxidation, hydrolysis, reduction
  2. concentration of toxins
  3. selective browsing
111
Q

Concentration of toxins

A
  • take toxins out of leaves they eat, metabolize this toxin to the brightest part of animal
    (clams - black part = neurotoxins)
  • frog
  • ants innoculate toxic leaves with fungus.. ants eat the fungus.. they have resistance to the poison… fungus concentrates the poison

BIOL 215 (10 decks)

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