Final Exam Study Guide Flashcards
(84 cards)
1
Q
negative density dependence
A
- can help pull a population towards an equilibrium size range
- is stabilizing
2
Q
causes of negative density dependence
A
- intraspecific competition
- disease
- predation
3
Q
carrying capacity
A
- also known as K
- when population is at K, r is approximately 0
- it is a range, not a single range
4
Q
positive density dependence
A
- occurs when vital rates and/or population growth rate increase as density increases
- destabilizing
5
Q
at low numbers, positive density dependence is called…
A
the Allee effect
6
Q
Allee effect
A
arise via small-population breakdowns in mating behaviors or the ability to find mates
7
Q
biological mechanisms of the Allee effect
A
many of the famous Allee effects arise via small-population breakdowns in mating behaviors or the ability to find mates, or in the ability to collectively make necessary habitat modification or engage in successful cooperative feeding
8
Q
biological mechanisms of the Allee effect : mating and caring for young
A
- mate limitation
- cooperative breeding
9
Q
biological mechanisms of the Allee effect : foraging advantages
A
- detection and access to food
- cooperative feeding
10
Q
biological mechanisms of the Allee effect : predator-method
A
- predator detection/confusion/defense
- others driven by how predation changes with prey numbers
11
Q
genetic variation
A
the difference in the genetic makeup (DNA) of individuals or populations among the same species
12
Q
why is genetic variation improtant?
A
important for survival and adaptation of a species as it helps in terms of natural selection and evolution
13
Q
effective population size (Ne)
A
the number of individuals that effectively participates in producing the next generation
14
Q
which is smaller, census size or effective size of a population?
A
effective size of a population
15
Q
small Ne
A
bigger increase in genetic drift
16
Q
when is Ne highest?
A
at equal breeding sex ratio
17
Q
genetic drift
A
change in allele frequencies by chance
18
Q
what does genetic drift cause?
A
a loss of genetic diversity
19
Q
where is genetic drift most common?
A
in small populations
20
Q
what does a population bottle neck lead to?
A
genetic drift
21
Q
when does genetic drift occur?
A
occurs when an event drastically reduces population size
22
Q
how to measure genetic drift?
A
- depends on Ne
- essentially the number of individuals in a population who contribute offspring to the next generation
23
Q
gene flow
A
the movement of alleles between populations
24
Q
when does gene flow occur?
A
occurs when individuals join new populations and reproduce
25
gene flow keeps...
keeps neighboring populations similiar
26
low gene flow
increases the chance that two populations will evolve into different species
27
inbreeding
loss of heterozygosity and increased expression of recessive homozygotes
28
F IS
inbreeding due to preferential mating with relatives
29
F ST
- inbreeding due to genetic drift in a small population mating randomly
- a measure of loss of heterozygosity
30
loss of heterozygosity =
increase in homozygosity
31
F ST range
0-1
32
F ST range = 0
no loss of heterozygosity
33
F ST range = 1
complete loss of heterozygosity
34
inbreeding depression
the loss of heterozygosity and expression of deleterious recessive alleles due to inbreeding disturbs vital rates
35
example of inbreeding depression
- births
- deaths
36
migration
movement of large numbers of one species from one place to another, often round trip
37
dispersal
permanent movement away from population of origin to another population
38
immigration
dispersal into a target population
39
emigration
dispersal out of a target population
40
one-migrant-per-generation (OMPG) rule
- typically maintains genetic diversity
- balances local adaptation
- independent of population size
- migrant has to have the same probability of breeding
41
how to measure connectivity/dispersal
- mark mark-recapture methods
- radio telemetry
- VHF & acoustic telemetry
- satallite transmitters
- genetic assignment test
42
how to measure connectivity/dispersal: mark mark-recapture methods
- great for tightly colonial species
- great for heavily harvested species
- need to know where to look for dispersing animals
43
how to measure connectivity/dispersal: radio telemetry
- mark animals with a radio transmitter
- follow them
44
different types of radio telemetry
- VHF
- acoustic
- satellite
45
how to measure connectivity/dispersal: VHF & acoustic telemetry
- easier to find dispersers than CMR
- limited by range of the transmitter
46
VHF & acoustic telemetry: limited by range
- which is limited by its size
- aircraft and now drones can help search
- freshwater & marine applications
47
how to measure connectivity/dispersal: satellite transmitters
- mark animals with transmitters
- sit at your desk and let a satellite track them
- good for broad scale movement but not always extremely accurate
- expensive and relatively heavy
48
how to measure connectivity/dispersal: genetic methods - assignment test
designed to directly detect individuals that disperse from their population of birth
49
metapopulations
population of populations
50
habitat occurs in ________ patches
discrete
51
dispersal occurs ________ patches
between
52
are all patches created equal?
no
53
source population
serve as a net contributor to the metapopulation
54
sink population
population that drains the metapopulation
55
ecological/evolutionary traps
- human created sink habitats
- preferentially chosen over better habitats but far less suitable
56
corridors
- help restore connectivity
- positive effects on BIDE components
- bridge for Christmas Island Red Crabs
- Trans-Canada Highway in Banff National Park
57
translocation/reintroduction
- help restore connectivity
- human mediated physical translocation of animals may be required to avoid extinction
- demographic rescue
- population augmentation
- reintroduction
58
five categories of anthropogenic stressors
- conversion of land and sea
- overexploitation through harvest
- invasive species
- pollution
- climate change
59
three main types of responses to stressors
- move to a more appropriate abiotic environment
- locally adjust in place
- head towards extinction as vital rates decrease
60
distribution shifts
- move
- adjust
- decrease
61
distribution shifts: move
climate change-induced movements: poleward and/or higher in elevation
62
distribution shifts: adjust
when faced with a tough challenge a species can deal with it aka adjust
63
phenotypic plasticity
- ability of individuals to change in response to their environment
- occurs within an individuals lifetime
64
evolution
- changes in genes over generations, facilitated by natural selection
- can occur fairly quickly
65
connectivity
connectivity among populations may be as important as dynamics within component subpopulations
66
Nt+1 = Nt + B + I - D -E
connectivity equation
67
why is connectivity important?
- persistence and fluctuation of populations
- rescue effects
- synchrony
68
colonization of new sites
permits response to changing environmental conditions
69
recolonization
increase persistence of suite of populations
70
genetic rescue OMPG rule
- at least one migrant individual. per generation is necessary to prevent significant divergence in allele frequencies among subpopulations
- minimize the loss of heterozygosity that could lead to inbreeding depression allowing the local adaptation among subpopulations
71
what caused the reduction in genetic diversity?
- predation
- habitat destruction
- hunting
- inbreeding
72
goal of genetic rescue
- introducing genetically diverse individuals into small, isolated populations with low genetic diversity
- to restore species to full genetic health so they can thrive in the wild without further intervention
73
genetic rescue aims to...
increase genetic diversity and minimize inbreeding to enhance the fitness and adaptability of populations
74
how does genetic rescue occur?
- occurs naturally
- also facilitated to safeguard at-risk populations and enhance their ability to adapt to environmental changes
75
genetic rescue
to increase a populations fitness by introducing new genetic variation
76
species characteristics of higher extinction risk
- lower abundance
- restricted range/endemism
- higher speciation
- larger body size
- longer generation time
- shorter dispersal rate
- higher human need
77
3 stochastic factors that small populations are vulnerable to
- demographic
- environmental
- genetic
78
demographic stochasticity
mean vital rates are probabilistic
79
environmental stochasticity
drives random changes in vital rates
80
genetic stochasticity
- arises from genetic drift
- can lead to inbreeding depression)
81
extinction vortex
- human-caused deterministic stressors & stochastic stressors interact
- make small populations smaller, eventually leading to their collapse
82
The Minimum Viable Population (MVP) Concept
- 50-500 rule, expressed in terms of the effective population size
- not the best method
83
MVP concept: short term
Ne ≥ 50 to minimize short-term loss of fitness due to inbreeding
84
MVP concept: long term
Ne ≥ 500 to ensure long-term maintenance of genetic variation/preservation of evolutionary potential
