Final Exam - Community Ecology - Lecture 14 - Fill in the Blanks Flashcards

1
Q

Food chain length depends on the amount of ________ _________ ________ (_).

A

Potential primary productivity or G

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2
Q

What are the names of the four major hypotheses on why food chain lengths differ?

A

1 - Energy limitation hypothesis
2 - Dynamic stability hypothesis
3 - Ecosystem size hypothesis
4 - Productive space hypothesis

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3
Q

_____ _______ hypothesis: longer food chains are less resilient so disturbance frequency/intensity limit food chain length.

A

Dynamic stability

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4
Q

________ ______ hypothesis: large ecosystems support more individuals and more species.

A

Ecosystem size

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5
Q

______ _______ hypothesis: food webs are inefficient; more productive environments support longer food chains.

A

Energy limitation

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6
Q

_______ ______ hypothesis: ecosystem size and productivity act together.

A

Productive space

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7
Q

To determine which factor affected food chain lengths in lakes, researchers performed treatments that included:
1 - ___________ alone
2 - __________ alone
3 - Combination of 1 and 2
(note that the lines may represent more than one word)

A

1 - Productivity

2 - Ecosystem size

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8
Q

Problems in testing food chain lengths hypotheses has been the inability to measure _____ _____ _____ and _________ _____.

A

Food chain length and ecosystem size

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9
Q

Post et al., used ______ _______ techniques to determine food chain length (maximum trophic position)

A

stable isotope

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10
Q

In stable isotope analysis, Carbon changes little through the food web, but is used to determine sources of _______.

A

energy

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11
Q

Productivity for small, medium and large lakes:

Maximum trophic position did ___ __________ with increased productivity

A

not increase

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12
Q

The conclusions of the Post et al (Stable isotope), study was that:
1 - Found ________ _____ was the ONLY factor that determined food chain length
2 - suggests that factors related to food chain length are not resolved
3 - At present, ________ _____ followed by ________ hypothesis are main factors

A

1 - ecosystem size

3 - Ecosystem size; productivity

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13
Q

Charles Elton on Food Chains vs. Food Webs:
- Food chains were “limited to _____ or _____ ______”
- Several food chains occur linked together as a food web
Chains and webs used to illustrate __________ in _________: (such as predator prey, host/parasitoid and mutualistic relationships)

A

1 - four or five links

2 - interactions in communities

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14
Q

Nodes (S) (definition)

A

the organisms that occur in the food web

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15
Q

Links (L): generally given as arrows to show the direction/strength of the _________ or ___________.

A

Interaction or relationship

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16
Q

Linkage density is given by the equation: /.

A

L/S
where,
L is the number of links and S is the number of nodes

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17
Q

What is connectance?

A

Number of observed links in the network.

given as a proportion of observed links to total possible links

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18
Q

Increased connectance promotes _________ in the food web.

A

Stability

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19
Q

Chain length: the number of _____ ______ in the chain or web.

A

Trophic levels

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20
Q

Source webs: all species in the web arise from the ______ _______ _______.

A

Same source species

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21
Q

Sink webs: where feeding relationships lead to a _____ ____ ________.

A

Single top predator

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22
Q

Community web (definition)

A

The entire set of feeding relations possible in a community (never fully realized)

23
Q

Connectedness web:

  • illustrate _______ ________
  • trophic links are given as arrows pointing to the consumer
  • No indication of ________ _________
A

1) Feeding relationships

2) Interaction strengths

24
Q

Green food webs:

  • Food webs with ______ _______ at the base
  • _____ energy channels
A

1) Primary producers

2) fast

25
Brown food webs: - Food webs with ________ at the base - ____ energy channels
1) Detritus | 2) Slow
26
Energy flow webs: - illustrate the pattern of _____ _____ through the community - Difficult to build - it is hard to get such difficult information - _______ ____ is not a good indicator of _________ _______ between species at different trophic levels - Considers Lotka's _________ concept of the ecosystem and Odum's depiction of the ecosystem as a _____ diagram
1) Energy flow 2) Energy flow; Interaction strength 3) thermodynamics; flow
27
``` Food webs are ______. Energy is lost via: 1) ______ energy - used to produce indigestible structures 2) ______ energy - lost as heat 3) _______ energy - nitrogenous wastes ```
- inefficient 1) Egested 2) Respired 3) Excreted
28
_________ energy = ingested - egested energy
Assimilated
29
_________ = assimilated - respired - excreted energy
Production
30
Energy available at each level of the food web depends on the ___ ________ ________ at the base of the web and _________ ________ between trophic levels
1) Net primary production | 2) Transfer efficiency
31
Plants use 15-70% of the energy they absorb for maintenance = maximum 30-85% for assimilation by herbivores BUT, energy transfer is ______. Only _-__% of energy available at one level is ________ to the next
Energy transfer is inefficient. Only 5-20% of the energy available at one level is assimilated by the next.
32
What is net production efficiency?
The ratio of energy contained in production to total assimilated energy (= production/assimilated energy)
33
Net production efficiency is ____ for active, warm blooded animals and ____ for sedentary, cold-blooded animals.
1) High | 2) Low
34
What is the equation for assimilation efficiency?
Assimilation efficiency = assimilation/ingestion
35
According to Raymond Lindemand, assimilation efficiency is the fraction of energy entering one trophic level that is ______ onto the _____ _____ _____. Transfer is ________. And this is why food chains are _____.
1) passed onto the next higher level. 2) Inefficient 3) Short
36
Functional webs: 1) illustrate the _______ of populations of each species in the web on the ______ ______ in the web 2) Size of the arrow represents the ________ of the __________ 3) Communities include _____ and _____, _____ and _______ interactions. 4) Not all interactions are _______ _________
1) impact; other species 2) strength of the interaction 3) weak and strong; direct and indirect 4) equally important
37
How does one determine interaction strength? - Experimental manipulation: 1) Remove ______ from the _________ and observe what happens to the other _______
1) Species; community; species
38
Indices of interaction strength: N = ____ [normal condition] (sentence answer) D = ______ [Deleted predator] Y = abundance of _______ Py = proportional abundance of the ________ t = time
``` N = abundances of prey when predators are present D = number of prey without predators Y = abundance of predators Py = proportional abundance of the predator ```
39
Paine's index = (N-D)/DY - Quantifies the effect of the ______ or _______ on the ________ _______ in the community - The dominant resource has the potential to form a _________ in the ________ of the consumer
1) predator or consumer; dominant resource | 2) monoculture; absence
40
Community importance = ((N-D)/NPy)) - Quantifies the effect of a ______ relative to its ________ - Distinguishes ________ from dominant species in the community
1) species; abundance | 2) Keystone
41
Dynamic index = ln(N-D)/Yt | - Compares the log ratio of _____ abundance when predators are _______ to when predators are ________
1) Prey abundance when predators are present to when predators are absent
42
``` What about observational data? (Bascompote et al.) IS = [(Q/B)j x DCij]/Bi Where, IS = ________ _______ Bi = _____ of the ______ ```
``` IS = interaction strength Bi = biomass of the prey ```
43
Functional food webs: - research has show that, for multiple food webs that: - most food webs contain a ____ ______ and many ______ links
few strong and many weak links
44
Food web stability: | - simple communities were more prone to _______ _______ and fluctuations in ______ ________
Simple communities are more prone to (species invasions) and fluctuations in (species abundance)
45
Simple communities are ________ communities. | Complexity adds ________ to communities.
1) Unstable | 2) Stability
46
Robert May: | Modeled ecosystems by randomly assigning interaction strengths and showed that complex communities were _____ ______.
Less stable
47
McCann et al: weak interactions in complex communities dampen population oscillations = _______ _______
increased stability
48
Ricklefs: an omnivore is an organism with a broad diet, including both plant and animal foods; an omnivore feeds from _______ _______ ______.
Multiple trophic levels
49
Based on theoretic models, Pimm and Lawton predicted that it should be _____ __ ____ species that feed simultaneously both high and low in the food web.
Rare to find
50
Because omnivores can alter their diet, their populations tend to be _____ _____ due to the _______ effect.
More stable = refuge effect
51
Singer and Bernays: Due to switching behaviour, omnivores interact _______ with their food sources - weak interactions --> _____ food webs
1) Weakly | 2) Stable
52
Lafferty et al., estimate that 75% of links in food webs involve parasites: - including parasites _______ food chain _____ and _______
(Increases) food chain (length) and (stability)
53
If parasites stabilize food webs, why are they not included? 1 - Small in size (hard to identify and quantify) 2 - Complex life cycles 3 - May have multiple hosts at different _____ _____ 4 - Energy transfer is _____ to measure because _______ do not _____ their hosts 5 - Parasites affect host behaviour, altering ______ ________
3) trophic levels 4) hard; parasites; kill 5) interaction strengths