Intro to ecology shit Flashcards
1
Q
Whats exploitation, competition, amensalism, commensalism, and mutualism?
A
E = +/- C= -/- A= 0/- Comm = 0/- M = +/+
2
Q
obligate mutualism vs facultative
A
cannot survive without relationship vs can survive but not as well
3
Q
What do you need to do before determining organism relationship?
A
Test benefits for both sides
4
Q
What is the main focuse of ecology
A
negative interactions
5
Q
Preditor/herbivore-mediate coex; what are the conditions
A
presence of a keystone predator/herbivore that keeps ecosystem and relationships in check
-only if the pred/herb negatively effects the superior sp.
6
Q
Apparent competition
A
negative affect between sp though not competing directly over a limiting resc.
(maybe through common pred/herb)
7
Q
What is the outcome of apparent comp?
A
the sp that can have a higher P* (equilibrium) with the predator wins
8
Q
T/F: apparent comp is linked to explotatin comp
A
FALSE
9
Q
how to prove it is apparent comp
A
changes in abundance of one prey leads to reduced/increased of the other prey
10
Q
Whats intraguild predation?
A
Basic: common prey but one of the predators is prey as well for the other predator
11
Q
What is explotation comp? interference?
A
- indirect competition (eating more food)
- directly fightng over food/females
12
Q
How can IG prey exist with IG predator?
A
it is better competitor (lower R*) for the shared resource/common prey
IG pred does not die out because it has two resources (the shared and IG prey)
13
Q
Why is world green?
A
because preds keept herbs in check
14
Q
Exploitative Ecosystem Hypothesis
A
each trophic leve alternates between comp and predation
15
Q
Odd number trophic levels usually end up as
A
green worlds
16
Q
T/F: Trophic cascades can happen without actually eating prey
A
True : it can just scare away herbs from the area
17
Q
T/F: cascades cant occur over ecosystems
A
FALSE
18
Q
If direct links between trophic levels are stronger than IG links then…
A
Regular trophic cascade stuff happening
19
Q
If the IG is stronger than driect links in the Trophic levels then….
A
it may act in the opposite direction of regular TL if you remove one. (ex: removal of pred may increase plants, even though herbivores will increase)
20
Q
Rules fro 4 sp, 3 trophic level system
A
- keystone pred promotes coexistance
- trophic cascade effect : predation can indirectly increase resource
- apparent comp : predation on a productive consumer can allow existqace of a less productive consumer
21
Q
difference between food and interactino web
A
food web only has trophic interactions and describes enery flow and arrows not labled.
22
Q
Why use foodwebs?
A
easy to make, communicates lots of info (how sp. depend on one another; can make predicitons)
23
Q
S =
L =
C =
L/S =
A
- sp. richness
- trophic links
- connectance (L/S^2)
- link density/ trophic link per sp.
24
Q
consequences through trophic levels
A
-dramatic drop in enery level and biomass to top
25
What can flip trophic pyramids?
if the lower trophic level can support a large number of the level above (1 tree to 20 herbivores)
26
More productivity will have __ food chains, why?
longer
| more energy to be transfered to support more biomass; primary production can determine community structure
27
How would increase in resource abundance affect IG prey and IG pred?
R* met for IG prey then pred -> increase in pred -> decrease and eventual extinction of IG prey
28
If increased prod doesnt increase chain length that much it can increase __ and ___
trophic links and sp.
29
If increasing prod. adds sp. and links, why does food chain not increase as much?
though adding new top pred will increase chain.....
-it may change trophic position of top pred instead; add/remove intmd. preds; increase omni of top pred; no change/decrease in chain will occur.
30
What controls primary productivity?
Bottom up effect (odd levels)
(land = soil;temp water= nutrient availibility)
Top-down effect (even levels-complex webs)
-trophic cascades
31
List the 3 sp. that have single-effects on community structure
keystone
ecostystem engineers
dominant sp.
32
explain keystone sp. comm. structure effect
keystone has a disproporitionate effect on organisms
| -removal leads to decrease in diversity
33
Herbivore keystones - how do they do with keystone predictions
if low or high density of keyst. then less diversity, more diversity at medium density
34
How does productivity alter keystone effect?
increase resource for prey then increase in kyst. pred overall increase i biomass (higher K)
35
Removing kyst preds can ____ food webs
simplify
36
Describe eycosystem engineers
-modify abiotic environment therfore affects things that live there
37
Describe allogenic and autogenic
Physically change the environment by own actions (worms; beavers)
-change environment through their own structure
38
Descripe single sp. effect with dominant sp.
exerts stron influence on other sp BECAUSE of high biomass
-removal may or maynot have a large effect
39
descrive mechanism of climate change in relaion to shift in TL and productivity
metabolic rates change according to temp; effect of warming depends on botoom up (RC-resource controled) or top down (CC - consumer controled) food web
RC - primary productivity and herbs increase no shift in comm. structure
CC - warming strengthens top down- and shift ratio of herbs to PP (primary producers)
40
Invasive spp can also affect food web by
decreasing diversity
41
Robustness =
| what kind of webs are more robust?
amt of primary sp removal required to lower diversity
| -more connected webs ; decreases redundancy
42
Which is more abudnant? weak or strong linkes?
weak
43
T/F: lots of weak links make a web more robust
True
44
Increasing the predation of a non key pred does what?
decreases effect of keyst. pred on the prey
45
how does competition for resources effect the keyst effect
it slightly weakens it
46
How does adding trophic lvs change keyst effect
it is enhanced in ODD number lvs
| decreased in EVEN number lvs due to trophic cascades
47
How does feed web structure alter keyst effect?
lowering prey lowers keyst effect, less change in biomass - lower keyst effect
48
Effect of warming on keyst effect
warming increases effect on prey
49
Parasites ___ food web links
dominate ; increase diversity and connectance
50
What is sp richness
number of sp in community
51
what is sp evenness
realtive abundance (ratio of one to another)
52
Graph wise, what kind of slope does a more diverse ecosystem have?
Smaller the slope the more diverse it is, the more even it is
53
What does the Shannon Wiener index combine?
both sp richness and eveness is it he value of the diversity index
54
What is a key factor of stable ecosystems?
biodiversity - more sp = less prone to invasion
55
Stuff that affects biodiv. in space and time
- abiotic factors
- heterogeneity and niches (spatia-temporal)
- spacial patterns (latitude - area relationships - island biogeog.)
- succession and stability
56
Abiotic factors influencing species richness
temperature and moisture (highest in warm and moist)
57
Competitive exlusion has shown that coexisting sp. have different ____ and ____ allows for more of them
niches
| environmental heteogeneity
58
Paradox of plankton
so many sp of plankton in a simple envrionment (though lots of different nutrient levels for them to exist in)
59
What is the limit to heterogeniety and diveristy
lots of hetero low effect area per sp = lower pop = higher extinction risk = lower # spp
60
What does disturbance do
perturb stable environments and creating new patches are bare space for r-sp. to colonize
61
Intermediate disurbance hypothesis
just enough dist to have most diversity ( r and K )
62
Pred/herb -med coex ____ diversity and competition and invasive pred/competitors _____ it
increase
lower
63
Time since perturbation
helps determine speciation
| -tropics are older/less disturbed; more time for speciation, less ext rates
64
Environmental heterogeniety and plants?
one may cause the other, not sure which came first
65
Species area relationships
SAR = compare sp richness to the area samples
- usually from nested sampling areas
- shows tot. sp. div. and also turnover/composition between adjacent regions
- S=cA^z (higher z mean greater sp increase per area)
66
Mechs for species-area relationships
- #sp in area is a balance of immigration and extinction
- larger areas can support larger populations; lower ext rate
- large areas=big target for colonists
- large area has greater environmental hetero.
67
Island are ___ than mainland or large islands in speciation
steeper (higher z value)
68
Island biogeog. theory
the # of sp is controlled by sp. immigration/extinction rates
69
What is immigration rate equation
```
lambda = I - (I/P)S I = immigration, P = pool, S = sp. #
Intercept = max immigration rate I
```
70
ext. rate eq
mew = (E/P)S
71
T/F: Area itself, not habitat heterogeniety can have an effect on sp. richness
True
72
What is succesison? Primary? Secondary?
-change in organism communities following disturbance/creation of new area
- primary = on newly exposed area
- secondary = disturbance rattles community
73
Order of succession
pinoeer - mid succession - climax sp.
74
Two models of succession
facilitation - only pioneer sp. can colonize (environment modified by them)
inhibition- adults (any sp) able to colonize; inhibit colonization of others - more long lived resistant sp.
75
Define biological invasions
sp. intentionally or accidentally transported out of native range and spread in new environment
76
Hypothesis why extreme effect of invasive sp.
native sp evolved in predator free enviro
apparent competition
disturbance to island ecosystem
77
What aspect of biotic community helps resist invasions
species diversity
78
What must be true for the natural enemies hypothesis
invader loses predators in exotic area
- predator had to have limited invaders growth in native area
- predators in exotic area have not much effect on invader
79
Extinction vs Extirpation
disspearance of sp. vs
| localized disappearance of all indv. of a population
80
Commonness and Rarity - what 3 factors?
geographic range
habitat tolerance
local population size
81
Rarity ex I , I, III conditions
large range, broad tolerance, small pop (sensitive to reduced density)
large range, narrow tolerance, large pop (sensitive to reduced area)
small range, narrow tolerance, small pop (very sens, to reduced density and area)
82
What is a metapopulation
collection of populations of the same spp that occasionally exchange individuals
83
Explain dynamics of metapopulations
large network of patches of suitable land that are separated by unsuitable
- connected through dispersal (c for colonization)
- extinction (m = mortality)
84
change in fract of occupied patches per unit of time =
fraction on patches taking in colonists x fract unoccupied patches - fract patches that go extinct
85
Extinction rates per island is ____ when there are more sp ____ per sp. on small islands
higher
higher
86
Why does extinction rate increase when sp increase on the island?
the more sp, the more each pop of each sp must decrease (carrying capacity)
more potential for competitive interactions with higher S
87
How are single populations more prone to extinction than multiple ones with no links?
the risk of extinction is "spread"
| sp can exist regionally even with high local extinction rates
88
Equilibirum equation for metapopulations
1- m/c
89
How to calculate habitat distruction
D*= V* = 1-m/c
says how much it takes to drive to extinction
V*destr = 1- (m/c) -D
90
For metapopulations what is the classic and the IBT suggestions
Classic = all patches have equal colonization ability
IBT = more isolated patches have lower probability of being occupied
91
Extinctions need to be _____ across the environment for the metapoulation to persist
uncorrelated
92
Describe Source-sink dynamics
source patches = at low density w/o immigration population growth is +
sink patches = "" pop growth negative
93
How do sink patches persist
Source patches must have emigrants
| -the rescue effect
94
What is the "living dead"?
spp destined for extinction
95
What is extinciton debt
the time it takes to reach a new equilib of sp after destruction
96
What is the relaxation index (I)
ratio of # of ext. yet to occur after time (t) to total that will occur
97
Single large vs several small areas for reserves
Single small is good for number of spp. an disaster less likely to wipe out
large is better for support and ext reduction for a particular spp. and contiguous area for large biomass
