Population Ecology Flashcards
1
Q
What are the earliest historical records of population ecology?
A
Leonardo Fibonacci “counted” rabbits (12th century)
Thomas Malthus “counted” people
2
Q
What is the term for a group of interacting individuals of the same species?
A
Population
3
Q
Define Population:
A
A group of interacting individuals of the same species
4
Q
What are some examples of modern (1800’s - 1920’s) population ecology?
A
- population dynamics of agricultural pests
- population spread of invasive species (how the populations change throughout space)
- fisheries (management of fish)
- game species (hunting)
- conservation (species are going extinct)
5
Q
A foundational element of population ecology found in the 1920’s used _____ to describe populations and how they change over time
A
mathematics (and some physicists)
6
Q
Why should we study populations?
A
- Manage natural populations
- Help understanding diseases and epidemics
- Help anticipate changes associated with changing climate
- Understanding human population dynamics
7
Q
______ models are foundational to population ecology
A
Mathematical
8
Q
What is an organism’s life history?
A
A record of major events relating to its growth, development, reproduction, and survival
9
Q
T/F life histories vary tremendously from one species to the next
A
True
10
Q
Define endangered species
A
Any species which is in danger of extinction through all or a significant portion of its range.
11
Q
What Act protects endangered species?
A
United States Endangered Species Act (1973)
12
Q
Define Life History Traits
A
Adaptations that influence growth, development, survivorship, and a variety of reproductive parameters for individuals of a particular species
13
Q
Define resource allocation
A
The quantity of key resources, such as energy and nutrients, that a parent can devote to reproduction.
14
Q
What are the two contrasting forms of natural selection?
A
r- selection and K-selection
15
Q
What does r stand for in r-selection?
A
per capita growth rate
16
Q
What does the per capita growth rate measure?
A
how fast the population can grow
17
Q
What are species with high reproductive rates that are most successful in unpredictable environments. (environments recently disturbed due to fires or floods)
A
r-selected species
18
Q
Why are r-selected species successful in unpredictable environments?
A
These species favor rapid development, reproduction at an early age, and the potential to produce a large number of offspring at rapid intervals.
19
Q
What does the K in K-selection stand for?
A
carrying capacity
20
Q
Define carrying capacity:
A
The maximum population size that can be supported or sustained by the environment
21
Q
What kind of individuals do k-selected species favor?
A
Individuals that compete effectively for resources in predictable and stable environments. These tend to have populations at or near carrying capacity
22
Q
K- selected species tend to have _______ competitive ability than r-selected species.
A
greater
23
Q
What kind of characteristics would be found in K-selected species?
A
- large body size
- parents that channel resources into the production of a few large offspring that can survive and reproduce in a highly competitive environment
24
Q
Does the dichotomy of an r and k selected species hold up across a range of species?
A
No, for example bats are some of the smallest animal species but they give birth to an individual bat one at a time, whom they lavish with large amounts of parental care.
But in the case of pacific salmon, they are very large and have delayed reproduction.
25
Does the r vs k model apply to plants well?
No, they devised an alternative classification scheme.
26
What type of plant species are favored when there are limited resources
stress-tolerant species
27
What do disturbed sites, such as places where plant biomass may be destroyed by abiotic factors or biotic factors favor?
Ruderals (rapid colonizers)
28
Are these classification schemes valuable even if they don't always work?
Yes. Because even when they fail they turn our attention to look more deeply into life history questions within ecology, this is also useful in assessing different tradeoffs in resource allocation that may not be obvious initially
29
Resting metabolic rate:
The amount of energy used by an organism over a given period of time while at rest in a thermally neutral environment.
(usually larger mass of an organism positively correlates with a higher resting metabolic rate-- although this is true, the metabolic rate PER UNIT is actually lower in larger animals than smaller animals)
30
What is another term for life history trait?
fitness component
31
List some examples of life history traits
- number and size of offspring
- age and size at reproductive maturity
- generation time
- age, stage, or size specific reproductive effort
- age, stage, or size specific rates of survival
- lifespan
32
What is the principal of allocation?
Organisms have limited resources (nutrients, energy)
| -- allocate resources to life history traits
33
Resource allocation:
the quantity of key resources, such as energy and nutrients, that a parent can devote to offspring -- this leads to trade-off between life history traits
34
What is meant by life history evolution?
- An increase in one life history trait is linked to a decrease in another life history trait
35
Define iteroparous:
Having multiple reproductive events over the course of a lifetime (almost all mammals)
36
Define semelparous:
Having only one reproductive event over the course of a lifetime (pacific salmon)
37
What group of insects survived extreme semelparity in the textbook?
Periodical cicadas
38
Define predator saturation in terms of periodical cicadas:
a possible explanation as to why periodical cicadas survived. There are simply too many cicadas present in the area for predators to eat them all
39
Define fecundity:
average number of offspring produced
| in plants this is the number of seeds produced, in mammals this is the number of eggs
40
Describe the fecundity advantage of semelparity:
Semelparous plants had higher mean fecundity
41
Define reproductive effort:
The amount of resources an organism allocates to a reproductive event
42
Define demography:
the quantitative study of the size and structure of populations, and of how populations change over time
43
What do demographers study?
Factors that influence changes in population size, including developmental rates and mortality rates
44
Define phenotypic plasticity:
An ability to change phenotypes in response to different environments
45
What does the reproductive model of iteroparous and semelparous reproduction explain?
Iteroparity is favored.
46
What does the demographic model explain?
Conditions under natural selection should favor semelparity:
1. long time to acquire resources for one reproductive event
2. low probability of surviving until the next reproductive event
47
Define phenotypic plasticity:
The ability of a single genotype to produce different phenotypes in response to different environments
48
Reaction norm:
This describes the plasticity of a single genotype
49
T/F
| We expect higher phenotypic plasticity in varying and unpredictable environments
True
50
Define recruitment:
The addition of new individuals to the population
51
Define dispersion:
Spatial pattern of distribution of individuals within a population
52
What are the 3 patterns of dispersion?
- random
- uniform (regular)
- clumped (most common)
53
What are the characteristics of random dispersion?
- Each individual has an equal probability of occupying any given space in the habitat
- Random dispersion are unusual in the natural world
- The location of one individual is independent of the location of another individual
- neutral interactions between individuals
54
What are the characteristics of a uniform (or regular) dispersion?
- Individuals tend to avoid other individuals with the result that they are spaced more evenly than in a random dispersion
- This is usually caused due to some sort of territorial interaction (remember that no dispersion is ever completely uniform)
55
What are the characteristics of a clumped dispersion?
- This is usually due to a shared attraction to either each other (in a species) or the same habitat and resources
- This is also the most common form of dispersion
56
Spatial distribution occurs over _____ ______
nested scales
57
What is the area that encompasses the entire spatial distribution of a species?
Geographic range
58
What are the two types of spatial distribution?
Cosmopolitan species
| Endemic species
59
What does cosmopolitan spatial distribution describe?
Geographically widespread species (rock dove that is found almost all over the world)
60
What does endemic spatial distribution describe?
Geographically localized species (red-ruffed lemur that is only found in madagascar)
61
Where will you find hot spots of high endemism?
Places such as the himalayas, hawaii, ivory coast, chile that have been geographically separated for a long time
62
What do we need to have to be able to measure the population of an area?
the abundance and density of an area
63
Define abundance:
The total number of individuals of a species present in a specified area
64
Define density:
of individuals in an area
65
South american sea lions are an example of
males and females having different dispersion patterns. and temperatures and how they can change throughout the day
66
Distribution, density, and dispersion all depend on what?
spatial scale
67
Define dispersal:
The movement of individuals from one location to another location
68
Migration:
The back and forth movement (intentional) of individuals between two locations
69
T/F insects survive the entire migratory trip
false, spring migration is much smaller than the initial fall migration
70
What type of study was performed on monarch butterflies?
Mark recapture study
71
Monarch butterflies depend on ________
milkweed
72
Early milkweed availability is correlated with ________
early migration
73
Dispersal affects range _______ and _______
expansion; contraction
74
What does % persistence mean
percent of former range still occupied
75
what does % expansion mean
percent of former range that has been expanded
76
what does % contraction mean
percent of former range that has been lost
77
what is the formula for % net change
% expansion - % contraction
78
What aspects of Mexico's Neovolcanic Belt make it an ideal destination for fall monarch migration
low but not freezing minimum air temperatures
79
How are plants dispersed?
By seeds (the only time they move in their life)
80
What are some abiotic factors that plants use to disperse seeds?
air
water
wind
81
What are some biotic factors that plants use to disperse seeds?
Birds, monkeys, bats, Humans
82
How do we measure seed dispersal?
Hard to quantify in general, but we are able to put up seed traps, this tells us where seeds go but no where they came from or how they got there. -- assumptions are made
- - we can also track animals through the forest using handheld telemetry, we then understand how the animals are moving within the environment
- also need to know gut retention time of the animal
- we can also place trackers on the seed itself
83
______ is the most important influence on terrestrial distributions
climate
84
compensating for environmental variation is metabolically costly, this poses limits on the _____ of the species
distribution
85
ecological performance is defined by:
survival, growth, reproduction, distribution and abundance of species
86
What does the niagara escarpment highlight for ecologists?
That adjacent habitats can experience dramatically different climatic conditions, which can influence the species that make up the ecological community
87
What plays a major role in the distribution of marine animals?
light
88
Which UV radiation is more damaging? UVA or UVB
UVB (wavelengths of 290-320 nm) thus proven false later because of the oceans ability to screen out uv radiation that can be damaging
This is hypothesized to be because the light under field conditions might stimulate DNA repairs mechanisms that offset some of the UVB damage to the Kelp's DNA>
89
Is the ocean an effective screen against UVB radiation?
Yes
90
Many prairie grasses have ____ ______ at or below the surface that can grow into new shoots following a fire
meristematic tissue
91
What is another adaptation to fire?
Serotiny, serotinous plants retain their seeds in the canopy for many years after the seeds mature and release them after exposure to heat (such as a fire)
92
Define nurse plants:
plants that provide a microenvironment that is conducive to saguaro survival during the early stage of life.
93
The three important nurse plants for saguaros are the _____, ______, and _______-
palo verde tree
the triangle leaf bursage
the mesquite tree
94
Naturalists observed an association with ______ and nurse plants
saguaros
95
Research by Drezner and Garrity demonstrated that saguaro distribution is not only associated with the absence of extreme cold but also with _____ ______
nurse plants
96
Define invasive species:
A non-native species that is introduced into a new habitat and that often adversely affects numerous species in the new habitat
97
Define ecological niche:
Set of environmental conditions and patterns of resource availability in which a species can survive, grow, and reproduce
98
T/F nurse plants provide less extreme thermal microenvironment below saguaros to protect them in early stages of life
True
99
T/F South side of saguaros stay warmer than the north side
true
100
Which of these is true of an r-selected species?
They are most successful in unpredictable environments
101
Almost all mammals are ______
Iteroparous
102
According to the demographic model, natural selection should favor semelparity under which two conditions?
- in plants that require a long time to gather enough resources to reproduce
- in plants with a low probability of surviving to the next reproductive event
103
Describe phenotypic plasticity:
One genotype producing different phenotypes in different environments
104
What is the most common type of dispersion found in nature?
Clumped
105
What is dispersal?
The movement of individuals from one location to another
106
Why are mammals excellent for studying distribution
Many non-scientists want to see them and are happy to report their sightings
107
The factor with the most important influence on terrestrial species distribution is ________
climate
108
In the study of nurse plants and saguara cacti, researches found that:
Nurse plants provided thermal protection to saguaros
109
A species niche consists of:
All environmental conditions that permit a species to exist
110
According to the resource hypothesis, invasive spcies:
Experience a more ideal combination of resources in the new habitat
111
T/F The distribution of a species is related to its niche
True
112
saguaros prefer _____ soil types and cannot survive in _____ soil
coarse; fine
113
Define fundamental niche:
The potential set of abiotic environmental conditions/resources in which species can grow, survive, and reproduce, in the absence of interactions with other species (this is seldom observed)
114
Define realized niche:
The potential set of abiotic environmental conditions/resources in which species can grow, survive, and reproduce in the presence of interactions with other species (competitors and predators)
115
What is the difference between the fundamental and realized niche?
The presence of biotic factors is found only in the realized niche
116
The rainbow melt is an _______ fish
anadromous
| spends most of its life at sea and moves to freshwater to breed
117
T/F because of the migratory patterns during mating and human interaction, the rainbow smelt have adapted new habitats and increased their niche.
True
118
Lakes with smelt tended to have ______ phosphorus levels and ______ disturbance values
lower; lower
119
T/F a species distribution is dynamic and our evaluation of its niche based on the distribution will always be imperfect
True
120
What is likely to happen to fundamental niches as global temperature increases?
Shifts in niche space
121
T/F range expansion of invasive species is a global challenge
True
122
What are the size ideal population characteristics?
- distinct individuals
- nonmotile individuals
- small geographic range
- large individuals
- small population size
- friendly environment
123
Define distinct individuals:
Possible to distinguish an individual from others
124
Define nonmotile individuals:
Individuals that can't escape being counted or wont get counted multiple times
125
Define small geographic range:
Great distances don't need to be traverse for an accurate count
126
Large individuals:
Individuals can be seen
127
Small population size:
It is possible to count all the individuals accurately
128
Friendly environment:
Humans can spend enough time in the environment for accurate censusing
129
Define unitary organisms:
Each individual is a unit, and presumably easy to count
130
Define modular organisms:
Develop and undetermined number of repeated copies of similar structures.
131
what is the formula for calculating population size in unitary organisms?
number of individuals in the sample / estimated probability of detection
132
Quadrat sampling is used to estimate population size for easy to count ______ organisms
unitary
133
define sessile:
fixed in one place (thus making organisms easier to count)
134
Define quadrats:
sampling areas
135
Why do modular organisms make it difficult to define an individual?
They have an undetermined number of copies of similar structures
136
Accumulation curve analysis is used for organisms that are:
Dangerous, endangered or elusive
137
In cases where there is no obvious unit that can be counted, ecologists may measure the ______ or ____ ___ of the organism
biomass; dry weight
| although these are invasive
138
Which of the following methods of measuring population size of modular organisms, like fungi, is both noninvasive and may rely exclusively on quadrat analysis using digital cameras?
Measuring percent cover,
Digital cameras can be taken of the quadrat, and the percent cover can be evaluated by a computer analysis of the image
139
What does discrete population life histories mean?
Species produce offspring at discrete time intervals, usually during a specific season
140
What does continuous reproduction life histories mean?
Individuals have the potential to reproduce at any time during the year.
(humans fit this)
141
Seed bank:
Where many annual plants may shed their young embryos in the soil whee they may accumulate over several years before germinating
142
The gray wolf, canis lupus, is an example of a species with a ______ reproductive life history
discrete
143
T/F The geometric growth model assumes that the changes yearly are the same
True
>1 growing
1 stable
<1 shrinking
144
Which species have continuous reproductive life histories?
Bacteria
145
Define the exponential growth model:
This model uses differences between birth rates and death rates to project changes in population size.
146
r:
per capita growth rate
147
intrinsic growth rate:
growth rate when there is no competition or predation
148
Define metapopulation:
a group of local populations inhabiting networks of somewhat discrete habitat patches
149
Define population density:
The number of individuals per unit area
150
Density independent factors:
Factors that will influence the population growth rates the same way regardless of population density
151
List some examples of density independent factors:
temperature, moisture, unpredictable disturbances, storms, mudslides, rock falls
152
Density dependent factors:
reduce population growth rates as population density increases
153
Examples of density-dependent factors:
disease and competition
154
Recruitment:
the stage of a plants life when it transitions from a seed to an established seedling
155
carrying capacity
signified as K: maximum population size that can be supported or sustained by the environment
156
As population increases, we wish to _____ the value of dn/dt, so that population growth rate ____ as population nears the carrying capacity, and population growth rate _____
decrease; slow; stops
157
as population size increases, the unused portion of the cc _____
decreases
158
Population size (N) is stable when
n=k
159
paramecium ______ the logistic growth model
support
160
The majority of ugandas population is _______
younger
161
Define population viability analysis:
the quantitative analysis of extinction risk that allows ecologists to recommend management options to improve the prognosis for continued survival of a population
162
single site PVA's apply to
a single population
163
Count based PVA's apply yo
populations at multiple points of time
164
What is the key to PVA's
all individuals are assumed to be equivalent toe ach other in characteristics such as age and survival and reproduction
165
the allee effect predicts that
very low density populations have a lower per capita population growth
166
r0 is the:
net reproductive rate
167
Which of the following is a key component of connectivity (with respect to colonization) by Hanski and colleagues?
distance from population to focal patch.
168
Metapopulation:
a population broken into sets of sub populations held together by dispersal or movements of individuals among them ( a population of populations )
169
Larger patches:
- contain larger population size
- more diverse habitat
- lower emigration
170
Higher patch density:
- more immigration from nearby patches --> lower extinction rates
171
Why are small populations more prone to extinction?
- lower genetic diversity
- more prone to chance fluctuations
- alee effect: low density populations may have lower per capita population growth rate r
172
connectivity influences _____ rates
colonization
173
as connectivity increases, colonization exponentially _______
increases
174
human mediated effect examples:
- habitat fragmentation
- habitat destruction and degradation
- non native species
175
enemy release hypothesis:
- invasive plants will have more pathogens in native range
176
EICA hypothesis:
evolution of increased competitive ability
