Competition/Predation Flashcards

1
Q

what are the two definitions for interspecific competition

A

1) the simultaneous requirements by two or more species for a resource that occurs in limited supply
2) any use or defense of a resource by one species that reduces the availability of that resource to other species

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2
Q

what is a resource

A

any substance that leads to changes in individual or population growth if the substance is increased or decreased

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3
Q

was nitrogen determined to be a resource

A

for plants yes, major. For humans no

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4
Q

Liebig’s law of the minimum

A

growth is not dictated by the total resources available, but the scarcest resource (limiting factor)

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5
Q

What is the competition exclusion principle or ‘gauses’s law of competitive exclusion’

A

2 species with the same niche cannot coexist

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6
Q

Grain Beetle situation

A
  1. 2 degree difference in environment switches competitive ability of 2 beetle species
    - habitat diversity
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7
Q

what did the ocean study discover

A

nitrogen-iron co-limitation

- need to add both things for organisms to grow

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8
Q

Evidence for interspecific competition in nature

A
  1. Habitat shifts in allopatry and sympatry
    2) Character displacement
    3) Habitat differences and resource partitioning
    4) Allelopathy
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9
Q

Habitat shifts in allopatry and sympatry

A
  • when species separated do one thing

- when put together, they will change their habitat to stay away from eachother

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10
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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11
Q

habitat differences and resource partitioning (2)

A
  1. the ghost of competitions past

2. competition in the present

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12
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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13
Q

competition in the present

A
  • invasive species
  • frequently leads to the displacement of native species that occupy similar habitats
  • e.g. starling was introduced. very aggressive, space competition
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14
Q

allelopathy

A

chemical competition in plants and animals

- the release of chemicals by one species in order to reduce growth/survivorship of another species

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15
Q

example of allelopathy

A

black walnut trees secrete jugalone which is highly toxic and kills/injures other plant species within a 20 m radius
- some species r resistant to jugalone

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16
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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17
Q

niche

A

how an organism makes its living

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18
Q

elton’s niche

A

the role of a species in a community

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19
Q

hutchinson’s niche

A

all biophysical conditions that characterize the life of a species

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20
Q

fundamental niche

A

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

21
Q

realized niche

A

the actual multidimensional space that a species can occupy taking into account biotic factors such as predators, competitors and parasites (a lot smaller than fundamental niche)

22
Q

how to calculate co-existance?

A

d/w
if d/w < 1 : no coexistance
if d/w > 3 : full coexistance

23
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
24
Q

biogaphy

A

the biological consumption of things

25
Q

Types of biogaphy

A
  1. Carnivory
  2. Herbivory-grazing
    - browsing (eats wood)
  3. parasitm and parasitoids (parasitic wasps)
  4. pathogens
  5. scavengers and detritivores (consumption of dead plant or animal material)
26
Q

Graph. Number of prey eaten per predator over density of prey

A
  • linear graph doesn’t often exist in nature
  • usually steep slope then begins to hit a asymptote on x-axis
  • predator gets full
  • can also be like an S, with a low slope on the bottom
27
Q

COMPENSATORY PREDATION

A
  1. at low densities, predators have a hard time finding their prey
  2. prey switching (go for most common type of prey)
  3. search image (only go for one type of prey)
  4. aggregated responses of predators (all predators come together, focus on areas where prey is v dense)
28
Q

functional response curves for: proportion of prey population consumed over prey density

A
  1. Straight horizontal line
  2. straight line, negative slope
  3. upside down u kinda… low prey densities it is harder for predators to find prey but as it goes up more prey is consumed
29
Q

what do virtually all predators target

A
  • juveniles

- post reproductive adults

30
Q

why do they target juveniles/post reproductives

A

low cost of injury

  • exception: fishing
  • graph kinda like a U - if age is x-axis
31
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)
  • not enough prey for them?
32
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.

33
Q

Leibig’s Law of the minimum

A

growth is not determined by resources available, it is determined by the MOST limiting factor

34
Q

muskrat predation

A

most mink predation on muskrats occured on the ones that didn’t have a territory

35
Q

What animals did this also happen with

A

Caribou when they killed the wolf predators

  • numbers exceed K and then crash
  • wolves limit the maximum prey density
36
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
37
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
38
Q

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

A
  • under 1 year (young)

- when dingoes present more pigs are in the 2-5 range, not many young

39
Q

Do predators limit prey density?

A

No: if leibig’s law of the minimum is acting
Yes: if carrying capacity has been exceeded
Yes: when native prey have no defenses against non-native predators

40
Q

average biomass ratio of prey to predator ENDOTHERMS

A

0.3:100

41
Q

ratio of biomass of prey to predators in ECTOTHERMS

A

1: 5

20: 100

42
Q

exploitation rate of prey by each predator species

A

average ~ 5% for each predator species

43
Q

what is the fastest predator exploitation rate

A

Human predators

  • exploiting 14x higher than other predators
  • because we are targeting reproductive adults
44
Q

defenses against predators

A
  1. camo, crypsis, conspicuous
  2. speed, agility, stamina, protean behaviour
  3. autotomy - limb release
  4. armour.. spines
45
Q

conspicuous defense

A

bright, scary colouration

  • usually poisonous or noxious
  • sometimes capable of producing injury
  • predators learn to minimize contact
46
Q

Mullerian mimicry

A
  • poisonous species mimic eachother (similar colour patterns)
  • butterflies
47
Q

Batesian Mimicry

A

a non poisonous species mimics a poisonous/stinging species

48
Q

batesian mimicry examples

A
  1. hoverfly mimics yellowjacket wasp. Hoverfly cannot sting

2. butterflies