10/11 quiz Flashcards
1
Q
what is the purpose of survivorship curves?
A
to assess patterns of survival in a population
2
Q
what group of individuals does a survivorship curve follow?
A
a single generation - a cohort
3
Q
what is plotted on survivorship curves?
A
the number of individuals still alive at that stage
4
Q
type I curve
A
most individuals survive until old age
typically produce few offspring and have parental care
5
Q
why do type I curves have low offspring mortality?
A
able to have parental care bc most individuals live until old age
6
Q
type II survivorship curve
A
individuals have a constant chance of being killed at any point in life
small birds and mammals that are killed heavily by predation
7
Q
type III curve
A
individuals have a low chance of survival when young, but survive well if they can make it to adulthood
typically lots of offspring but no parental care
8
Q
what are factors that can impact survivorship curves?
A
habitat quality and sex
9
Q
what’s something to note about survivorship curves?
A
the y-axis is logarithmic
10
Q
how can habitat quality impact survivorship?
A
food quality and predation
11
Q
how can sex impact survivorship?
A
differences by sex, such as competition for mates
12
Q
what are dispersion patterns?
A
patterns of spacing among individuals
13
Q
what are the three types of dispersion patterns?
A
clumped, uniform, and random
14
Q
what influences cause clumped dispersion?
A
positive biotic interactions (btwn individuals)
common resources
15
Q
what influences cause uniform dispersion?
A
negative biotic interactions (competition and territoriality)
16
Q
what influences cause random dispersion?
A
absence of biotic interactions
not very common
17
Q
example of clumped dispersion
A
penguins
to conserve heat and to be social
18
Q
example of uniform dispersal
A
shrubs
19
Q
example of random dispersion
A
dandelions in lawn
plenty of resources and can thrive anywhere
20
Q
census
A
all individuals in population counted
21
Q
when do censuses work best?
A
when individuals are large and easy to count
22
Q
why are censuses inherently inaccurate in the US?
A
its too large of a population and territory
23
Q
what does population estimation work well with?
A
sessile species using quadrats
can leave permanent markers to come back to
24
Q
what does mark-and-recapturing do?
A
allow for sampling of mobile species
25
how do mark-and-recapture samplings work?
mobile species are marked with a band, tattoo, or radiotracked
26
what mathematical model does mark-recapture sampling use?
Lincoln Index
N = nM/R
27
what do the variables in the lincoln index mean?
N : estimated population size
=
n : total number of individuals captured in first census
M : number of individuals captured during second census
/
R : number of marked individuals recaptured during second census
28
what are the assumptions of the lincoln index?
equal chance of recapture for all individuals in population
ratio between marked and unmarked individuals remains constant
individuals don't lose their mark
population is closed
29
what is meant by ratio staying constant with respect to marked and unmarked individuals?
we are neglecting death and predation
30
what is meant by all members of pop having an equal chance of recapture?
no one is "trap shy" or "trap happy"
31
what is meant by the population being closed?
no immigration or emigration
32
what are the factors that influence population size?
births, death, immigration, emigration
33
what is the first mathematical model for population growth?
N(t+1) = N + (births - deaths) + (immigration - emigration) *all at time t*
34
assumptions for the first population growth model
all individuals are identical (no age, genetic, or evolutionary differences)
birth and death rates are constant
no immigration or emigration
habitat is perfectly uniform
35
what are the modeling options if we are working with non-limiting resources?
if discrete generations -> geometric growth
is overlapping generations -> exponential growth
36
what is the modeling option if we are working with limiting resources?
logistic growth
37
how do populations grow?
in proportion to their size
38
what is the geometric growth model used for?
populations that vary due to seasonal changes in birth and death rates
many birds and mammals
39
what is lambda in geometric growth?
population growth rate constant
40
what value of lambda makes a population INCREASE?
greater than one
41
what value of lambda makes a population DECREASE?
less than one
42
what value of lambda makes a population STABLE?
equal to one
43
example of organism with discrete generations
emerald ash borer
new generation of adults each spring, all adults die that summer
no generational overlap
44
how do we calculation geometric growth for more than a year of change?
make lambda to the power of the year
5 year change -> N(0) * lambda^5
45
what are conditions in which geometric and exponential growth can occur?
when a new habitat or geographic range are established
exploiting temporarily favorable conditions
recovery after protection
loss of predator or competition
46
example of establishing a new habitat
killer bees on new continent
virtually unlimited resources
47
example of exploitation of temporarily favorable conditions
dandelion in empty lawn
can reproduce anywhere and has lots of resources
48
example of recovery following protection
whooping cranes
n = 22 -> 505
49
what are examples of organisms that use exponential growth models?
bacteria, many pest species, and humans
50
what does dN/dt mean?
instantaneous population growth rate
change in population over change in time
51
what does r mean?
per capita population growth rate
constant
52
what does r numerically represent?
birth rate - death rate
= ln(lambda)
53
what is r when population is increasing?
greater than zero
54
what is r when population is decreasing?
less than zero
55
what is r when population is stable?
equal to zero
56
how can we use the exponential growth model to calculation population size?
integrate growth over time
57
what is population growth affected by?
biotic and abiotic factors
58
what are biotic factors that can affect population growth?
predation, food supply, competition, parasites, pathogens, and mutualists
59
what is a bottom-up biotic factor?
regulating food chain from lower trophic levels
60
what is a top-down biotic factor?
regulating food chain from upper, predation, trophic levels
61
example of bottom-up biotic factor
El Nino warm waters flowing towards the Galapagos
decline in marine food base -> decline in penguin population
62
example of top-down biotic factor
decrease in marine predators -> increase in foraging fish -> decrease in zoo plankton -> increase in phytoplankton
63
what is the pattern of bottom-up biotic factors?
layers of the food chain experience the same direction of change
64
what is the pattern of top-down biotic factors?
alternating directions of the food chain layers
65
what regulates population growth rates?
biotic and abiotic factors
density independent and dependent factors
66
what are density-independent factors?
events that affect the same proportion of the population regardless of population density
regulates r but not N
often unpredictable changes
67
what are examples of density-independent factors?
hurricanes, flooding, unpredictable changes in temp, and volcanoes
68
what's an example of a density independent population regulation event?
all the monarchs freezing in Mexico due to an unexpected change in temperature
population change wouldn't impact result here
69
what are density-dependent factors related to?
darwin's theory of natural selection
70
how are density dependent factors related to another phenomena?
darwin's theory of natural selection:
each individual has a high potential reproductive rate
a lack of resources will eventually limit the population
intense competition and differences among individuals become an important source for natural selection
71
birth and death rates change as a function of ___?
population density
effectiveness increases as population size increases
72
what are some density-dependent factors that might affect population growth rates?
crowding
competition for food or sunlight
pathogen attack
pollinator attraction
73
what will happen to birth/death rates and dispersal as densities increase?
birth decreases
death and dispersal increase
74
how can hunting affect density and population growth rate?
kill a lot of animals, but then there's a lot of resources for the remaining animals to thrive off of
75
what do density-dependent factors do for the population?
serve as a negative feedback system
76
how do density dependent factors serve as a negative feedback system?
rate of growth slows as population density increases
77
how can we identify a density-dependent factor?
look for correlation between mortality or reproduction and population density
there will often be a time lag
78
what is carrying capacity?
an equilibrium population size, where populations should stabilize
79
what do logistic growth models show?
populations growing rapidly at first but then slowing as resources dwindle
population growth will hit zero and population size with stabilize
looks like an s-shaped curve
80
what population size do logistic growth models stabilize at?
carrying capacity, K
81
what is the logistic equation a modification of?
exponential growth equation
adds a term to reflect changes in population size as K is approached
82
what happens when N > K?
dN/dt is negative
population declines
83
what happens when N < K?
dN/dt is positive and population grows
84
what happens when N = K?
dN/dt = 0
population is stable
85
what do density-independent factors do to the population?
represent distrubance
potentially prevent population from reaching K because of unexpected events
86
we can predict population ___ and ___ using ___ ___
size and growth using mathematical models
87
stable populations fluctuate within ___ ___
narrow limits
88
what factors can impact population stability patterns?
density dependent and independent
89
can populations be stable if not a equilibrium?
yes!
but generally are close to it
90
what does the modification to the logistic growth model allow for?
consideration of unused opportunities for population growth based on carrying capacity
91
for multiple populations experiencing the same density-independent occurrence (hurricane, tornado, etc.), what would we expect the graphs to look like?
similar because the same effect will be happening across the area
92
for multiple populations experiencing the density-dependent occurrences, what would we expect the graphs to look like?
fluctuations between populations because they will tend to do different things
93
what causes populations to cycle?
regular environmental changes
intrinsic dynamics
interactions with predators or disease
94
what is an example of a regular environmental change that causes population cycles?
El Nino events -> decrease in resources -> density dependent
95
what are the types of intrinsic dynamics?
no oscillation, damped oscillation, and limit cycle
96
what are intrinsic dynamics?
a type of fluctuation in population size due to time delays that depend on population growth
97
what do no oscillation graphs look like?
normal logistic growth model, s-shaped curve
98
what is r when there is no oscillation?
r < 1
99
what are damped oscillations?
populations getting progressively closer to K
start big but bounce around getting closer
100
what is r in damped oscillation?
1 < r < 2
101
what are limit cycles?
population numbers alternate between high and low values until the population goes extinct from hitting 0
102
what is r in limit cycles?
r > 2
103
what does self regulation require?
organisms to have internal mechanisms to respond to population density
104
what is an example of an internal mechanism for population density control?
stress hormones to decrease reproduction or increase mortality
105
what is an example of population cycles due to predation/disease?
red grouse
parasite that reached peak-build-up every four years and would dramatically impact red grouse populations
106
how do vaccines use host-parasite relationships?
treat enough people to reduce parasite/pathogen burden to prevent significant population declines
107
environmental variations tend to be ___, while fluctuations in many populations are ___
random and non-random
108
growth rates are ___
density-dependent
109
regulatory factors vary over ___
space
110
populations are spatial mosaics because they have different ___ ___ in different ___
regulatory processes in different areas
111
life history
organism's lifetime pattern of growth, reproduction, and death
112
what is the life history strategy?
patterns in growth and development
life span
timing and quantity of repoduction
113
example of long life - few offspring organism
rhinos
114
example of short life - many offspring organism
mosquitoes
115
what can be identified by an organism's life history?
mode and age of maturity for reproduction
size and number of offspring
parental investment and parity
life span
116
what is parity?
number of reproductive events
117
why don't we evolve life history to maximize fitness?
there are tradeoffs due to limited resources
"problem of allocation"
118
there is an ___ energetic investment for a particular life history component
optimal
119
investing beyond optimal energy for a particular fitness components can...
overall reduce fitness
limited energy to other important functions
120
what do high mortality rate adults favor?
current fecundity
breed now, could die tomorrow
121
what do long lifespan adults favor?
delayed reproduction
save energy, you have time
122
example of high mortality rate organism
swainson's thrush
lifespan = 3-4 yrs
produces 1-3 broods per year
123
example of long lifespan organism
leach’s storm-petrel
lifespan = 30-40 yrs
produce 1 young per year
124
benefits of early breeding
increase fecundity
125
costs of early breeding
reduced survival to older age bc of energy allocation
reduce fecundity at older age
126
indeterminate growth
organisms that don't have a typical adult size
fish, some plants, some invertebrates
127
fecundity is related to ___ ___
body size
128
increased fecundity in one year ...
reduces growth and future fecundity
129
example of optimal allocation
bird having 7 eggs per brood
5 -> one dominates and kills other chicks
9 -> parents can't properly care for young
130
what are the three key developmental features of life cycles?
embryo -> adult
presence of dormancy stages during development
development and constancy of organism's sex
131
direct development
adult develops from fertilized egg
no larval stage
132
indirect/metamorphic development
larval stage present
two radically different stages
133
example of direct development
dolphins or humans
134
example of indirect development
frogs or butterflies
135
costs of metamorphosis
significant energy expenditure
vulnerability to predation at certain stages
136
advantages of metamorphosis
specialization on different functions at different life stages
use of different ecological niches
reduced competition among larvae and adults
137
neoteny
adults retain larval forms but can reproduce sexually
more common in extreme environments
138
dormancy in development
flower in desert
resist harsh environmental conditions
seeds, spores, cysts
139
asexual reproduction
progeny are genetically identical to e/o and parent
clones
occurs in plants and some animals (corals, insects, fisk, snakes, birds)
140
parthenogenesis
producing eggs with two sets of chromosomes
all progeny are female
can produce with males, but can due in absence as well
141
what organisms can do parthenogenesis?
some insects, snails, reptiles, ...
