SimUtext Flashcards
(159 cards)
1
Q
a unit of heredity information that codes for a product such as a protein
A
gene
2
Q
alternate versions of a gene
A
alleles
3
Q
- such as humans
- two copies of each gene inheriting one from each parent
A
diploid organisms
4
Q
an organisms whose two copies are the same allele is what for that gene
A
homozygous
5
Q
an individual with two different alleles
A
heterozygous
6
Q
certain genotypes are associated with higher or lower what, depending on the local environment of the individual organism
A
fitness
7
Q
refers to how successfully an individual passes their genes to future generations
A
fitness
8
Q
What occurs when the heterozygous genotype for a particular gene confers higher fitness than do homozygous genotypes
A
heterozygote advantage
9
Q
What three conditions must be met for evolution by natural selection to occur?
A
- there must be variation within the population
- the mechanism that creates the variation within the population
- the variation must lead to differences in fitness
10
Q
an inherited disease in which people produce malformed red blood cells that are sickle-shaped instead of disc-shaped, despite high mortality this persists in some areas
A
sickle-cell disease
11
Q
a deadly mosquito-borne disease in which humans red blood cells are invaded by a protozoan parasite
A
malaria
12
Q
sickle-cell disease occurs when a person is homozygous for the sickle-cell allele (HbS) of what gene
A
hemoglobin
13
Q
Individuals with what genotype have increased fitness in environments where malaria is common
A
HbA/HbS
14
Q
New alleles are created through what
A
random mutations of DNA
15
Q
the persistence of a new allele in a population depends in part on the degree to which the allele confers a what which may depend on the local environment
A
fitness advantage
16
Q
a mechanism of evolution in which random events affect the frequency of alleles in a population
A
genetic drift
17
Q
What two mechanism are not mutually exclusive
A
genetic drift and natural selection
18
Q
when the relative fitness of a particular genotype is high what may have a larger effect on allele frequency than what
A
- natural selection
- genetic drift
19
Q
Genetic drift follows the rules of what and thus the size of a population influences the effect that genetic drift can have
- in small populations a particulars alleles frequency is more likely to become fixed and either disappear entirely or become the only allele circulating in the population
- in large populations allele frequency tend to remain relatively stable over time
A
probability
20
Q
a population in what is not evolving meaning its allele frequencies are remaining constant
A
Hardy-Weinberg equilibrium
21
Q
For HWE to occur what conditions must be met?
A
- no natural selection, all genotypes are equally adaptive
- no genetic drift, randomness is not a factor
- mutation
- no migration
- random mating, offspring genotypes are random combinations of parental alleles
22
Q
used to predict allele and genotype frequencies for a gene with two alleles in a population in this
A
HWE
23
Q
What symbols represent the frequency of the two different alleles
A
p and q
24
Q
What is the HWE equation
A
p^2 + 2pq + q^2 = 1
25
the frequency of individuals that are homozygous for the first allele
p^2
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the frequency of heterozygous individuals
2pq
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the frequency of individuals that are heterozygous for the other allele
q^2
28
HWE is a what that describes expected genotype frequencies in a population that is not undergoing evolution
- simplified systems describing expectations without influencing factors
- useful because they allow you to generate and test alternative hypotheses which posit that something interesting such as evolution is happening
Null Model
29
How can scientist test if evolution is occurring in a particular gene
they can measure the genotype frequencies in a population and compare the frequencies to those predicted by the HWE
30
if the difference between observed and expected frequencies is statistically significant the null hypothesis can be what which is used as evidence that the population is evolving
rejected
31
Use of simulated populations and the HW null model suggest that if malaria were to be eradicated the what associated with the sickle cell allele HbS would disappear and there would be strong selection against HbS unless sickle-cell disease were also effectively eradicated
heterozygote advantage
32
a change in the genetic composition of a population from one generation to the next
evolution
33
What two things are intertwined
evolution and ecology
34
Evolution is often facilitated by what and the resulting impacts can be ecologically important
ecological processes
35
What are the four mechanisms of evolution
- mutation
- natural selection
- migration
- genetic drift
36
What mechanisms are not exclusive of each other and often act simultaneously
evolution mechanisms
37
evolution by what happens when individuals with certain traits survive and reproduce at higher rates than others
natural selection
38
numerous examples from laboratories and natural populations demonstrate that substantial evolution in ecologically relevant traits does what
can happen rapidly, sometimes in just a few generations
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traits associated with what become common
survival and reproduction
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traits associated with what become rare
early death and reproductive failure
41
What theory applies to any population in which the requirements are met
natural selection
42
The theory of evolution can be framed in the language of what
modern genetics
43
evolution can be defined as change in what across generations or among populations
allele frequencies
44
When there are differences in phenotype that are at least partly due to differences in genotype and some phenotypes have higher what than others, then allele frequencies automatically change
fitness
45
Alleles associated with what become common
high fitness
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Alleles associated with what disappear
low fitness
47
Allele frequencies may also change across generations due to what which is evolution by genetic drift
purely random events that result in sampling error
48
a form of genetic drift that occurs when a few individuals from a source population establish a new population, usually the allele frequencies will be different in the new population than they are in the source population
Founder effect
49
What also occurs when individuals migrate from one population to another, if the migration alters allele frequencies in one or the other population
evolution
50
What can create new alleles in a population which changes allele frequencies across generation which leads to evolution
genetic mutation
51
What do not act exclusively of each other
the four mechanisms of evolution
52
In what evolution can occur via any combination of mechanisms acting simultaneously
natural populations
53
Understanding the mechanism of what helps researchers and farmers devise ways to control crop pests like the pink bollworm without encouraging rapid evolution of resistance
decent with modification
54
What populations evolve resistance to Bt toxins because normally rare resistant genotypes enjoy much higher fitness than susceptible genotypes on Bollgard cotton
Pink Bollworm
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What uses fields planted with patches of Bollgard and patches of normal cotton
The high-dose/refuge strategy
56
What is well protected against bollworms
Bollgard cotton
57
The normal cotton allows susceptible bollworms to survive reducing what
the fitness advantage associated with resistance
58
The evolution of antibiotic resistance in populations of disease causing bacteria is what
a major health concern
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What is ongoing but is unlikely to be a long term solution to the problem
The development of novel antibiotics
60
Other strategies are needed to help reduce the evolution of resistance in what
pathogenic bacteria
61
When resources are limited individuals must do what
compete
62
the complete set of conditions under which an organism could potentially survive and reproduce
fundamental niche
63
the subset of the fundamental niche describing the conditions under which an organism actually lives given limitations created by interactions with other species
realized niche
64
What states that no two species can coexist in exactly the same niche
competitive exclusion principle
65
occurs when individuals compete by consuming a shared resource
indirect or resource competition
66
What does direct or interference competition include
allelopathy, territoriality, preemption
67
occurs when plants release chemicals that inhibit the growth of their competitors
allelopathy
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describes the establishment by an organism or group of a defended area from which others are excluded
territoriality
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occurs when individuals prevent others from using a location by occupying it first
preemption
70
competition for resources among individuals of the same species
intraspecific competition
71
When resources are unlimited individuals in a population will not compete and the population will be able to grow how
exponentially at its intrinsic rate of growth
72
As population density increases intraspecific competition does what reducing the health of individuals in the population
increases
73
When resource limitation is such that a populations birth rate and death rate are equal the population is said to be at its what
carrying capacity
74
a simple model of population growth in the presence of a limited resource
logistic growth equation
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competition for resources among individuals of different species
interspecific competition
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What equations can be used to model competition between populations of two species
Lotka-Volterra
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instantaneous population growth rates
dN1/dt and dN2/dt
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per capita intrinsic growth rates
r1 and r2
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population sizes
N1 and N2
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carrying capacity with subscripts
K1 and K2
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what are alpha 12 and alpha 21
competition coefficients
82
describes the per capita of one species on population growth of the other
competition coefficients
83
viewed in phase plane and provide a graphical way of determining the possible outcomes of competition between two species
the isoclines of zero population growth for lotka-volterra competition equations
84
The lotka volterra competition equations predict that species can only coexist if what is stronger than what
intraspecific competition is stronger than interspecific competition
85
What are frequently violated in the real world and what does it lead to
the assumptions of lotka volterra equations and it leads to more complex outcomes
86
Numerous field studies have shown what is more important in natural settings
competition
87
some species are more likely to be what by competition than others
strongly affected
88
What of competition can vary among environments for example a can beat be in wet environments but b could beat a in dry environments
strength and outcome
89
There may be what in adapting optimally to different environments
trade-offs
90
What can lead to character displacement reducing the strength of competition between species
interspecific competition
91
other types of interactions between species can reduce what
the degree of competition within or between species
92
What is a key goal of epidemiology
to understand how infectious disease spread through populations
93
diverse and employ various strategies for infecting and growing within their hosts which provide diverse environments for them
pathogens
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occurs when a pathogen invades a host and then the pathogen population grows to the point where the pathogen can be transmitted to a new host generally the host is harmed in this process
infection
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What do human pathogens include
viruses bacteria fungi protozans and helminths
96
What typically target cellular structures and functions that are unique to the pathogen type so that the hosts cells are not harmed
natural and human made substances that fight infection
97
Human hosts defend against pathogens with two types of what
immune system response
98
includes barriers to entry and internal defenses is rapid and targets broad classes of pathogens
innate immune response
99
slower but more specific targeting particular pathogens immune system learns to remembers the pathogens its been exposed to so subsequent responses are much more rapid
acquired immune response
100
epidemiologists use models of disease spread to help understand disease dynamics and to predict the impacts of what
epidemics
101
the spread of disease in a population can be modeled by considering what happens to three categories of individuals which includes the susceptible, infected, and recovered
SIR model
102
What factors affect how fast a disease will spread and how many individuals will become infected
population density (N) transmission rate (B) and infectious period (L)
103
diseases basic reproductive number
R0
104
describes how many individuals an infected individual is expected to infect in a population of susceptible individuals, it is specific to the pathogen the host population and the environment
diseases basic reproductive number
105
R0 can be estimated as what
R0 = SBL
106
When can an epidemic take hold in a population
when R0 is greater than 1
107
although it is useful for many applications the basic SIR model often oversimplifies actual what however extensions to the model can improve realism
disease transmission
108
What cause the composition of most populations to change over time
births adn deaths
109
newborns lack immunity so births increase what which facilitate the ocurrence of disease cycles such as with measles in unvacinated human populations
the number of susceptible individuals overtime
110
occurs when a sufficient number individuals in a population are immune to a disease such that the disease will not spread through the population this can be achieved through vaccination or with immunity from previous exposure to the pathogen
herd immunity
111
pc is the minimum proportion of the population that must be immune in order to achieve herd immunity this threshold is related to the diseases basic reproduction number r0
critical immunization threshold
112
A higher value of R0 means what
that more individuals must be immune to prevent an epidemic
113
can slow the spread of disease, they are particularly useful when vaccines and drugs are not availiable
community mitigation strategies
114
What are some strategies that reduce the frequency of contact between susceptible and infected people
social distancing and quarantines
115
What lower the risk of transmission when a susceptible person contacts an infected one
wearing masks hand washing and condom use
116
community mitigation strategies can what
flatten the curve
117
What are two key benefits of flattening the curve
- reducing the number of infected people at the peak of an epidemic prevents health care systems from being overwhelmed
- delaying the timing of the epidemic peak allows for health care systems to build capacity and for researchers to develop new treatments
118
What are example of directly transmitted epidemics
covid and HIV/AIDS
119
What are examples of indirectly transmitted epidemics
giardia, dysentery from salmonella, and bubonic plague
120
occurs through person to person contact and includes diseases like colds covid and STDS
direct disease transmission
121
involves an intermediate agent, the agent may be inanimate as when dirty water spreads diseases like cholera, the agents may also be animate vectors
indirect disease transmission
122
What can adapt SIR models to describe the transmission of vector borne diseases like malaria by adding compartments that represent susceptible and infected individuals in the vector population
epidemiologists
123
may be infected themselves as with malaria or they may simply spread the disease by carrying pathogens without infected
vectors
124
What is a vector borne disease caused by the plasmodium parasite a protozoan, an epidemic in many parts of the world
malaria
125
requires both human and mosquito hosts provides multiple opportunities to disrupt transmission
plasmodium's complex life cycle
126
What creates challenges for controlling their spread
the fact that vector borne diseases are transmitted by non human organisms
127
all of what evolve over time
pathogens
128
What are the mechanisms that evolve pathogen evolution
mutations, heritable traits, natural selection, genetic drift, and reassortment
129
these often result either from spillover of a new virus from an animal population or from the creation of new strains through reassortment
pandemics
130
What do pathogens benefit by
effectively using the hosts resources to grow and reproduce which causes harm and can kill the host possibly before the pathogen spreads to a new host
131
pathogen evolution is influenced by
trade-offs
132
a critical environment variable that predictably influences biological processes at a range of scales from enzymes to species
temperature
133
many biological processes vary as described by a hump-shaped
temperature performance curve
134
peaks at an optimal temperature
performance
135
define the limits of performance called the tolerance range
the minimum and maximum temperatures
136
temperature often determines performance because it influences chemical reaction rates especially those that are controlled by what
enzymes
137
for many taxonomic groups species richness is correlated with what
mean annual temperature
138
ecologists are concerned that what will have increasingly dramatic impacts on Earth's biota because of the relationship between temperature adn performance
climate change
139
describes the short term behavior of the atmosphere
weather
140
describes its long term behavior over 30 years or more
climate
141
changes in climate are easier to detect when what which is why scientists often focus on changes in global means rather than on noisier local trends
signal to noise ratio is high and or data sets span a long period
142
show that during the last 30 years the northern hemisphere was warmer than during any other 30 year period in at least 800 years and probably 2000 years
proxy data
143
which includes reduced Arctic sea ice glacial retreat and reduced spring snow cover
cryosphere
144
altered bringing more frequent and severe doughts as well as more frequent and or intense storms
precipitation patterns
145
due to both thermal expansion and the addition of water from melting snow and ice
sea levels
146
over the past 40 years this has increased
heat energy stored in oceans
147
have been documented across most of the US due largely to earlier springs
longer growing seasons
148
reflect our current understanding of climate and allow scientists to test hypotheses about factors affecting it
models
149
A plants equilibrium surface temperature can be predicted from simple black body climate model that accounts for what
solar output, distance from the sun, albedo, and greenhouse gases
150
energy is emitted by the sun which varies over time
solar output
151
determines the amount of solar radiation energy intercepted by the plant
distance from the sun
152
the proportion of incident solar radiation that is reflected by the planet
albedo
153
produce the greenhouse effect further warming the surface of a planet with atmospheres containing them
greenhouse gases
154
What describe non equilibrium and incorporate climate feedbacks, some feedbacks like ice albedo are positive amplifying the effects of climate change while others like cloud albedo are negative dampening the effect of climate change
more complex climate models
155
why is teh climate warming
the earths global energy budget is currently out of balance is absorbs about 0.6 W/m^2 more energy than it radiates
156
more complex accounting for the effect of earths curved surface rotation and topography they are driven by coupled models of the atmosphere and ocean and they incorporate sea ice aerosols and biogeochemical cycles
Global Climate Models (GCMs)
157
both natural and anthropogenic forcing's have the potential to drive
climate change
158
climate change is affecting species in terrestrial and aquatic ecosystems
across the globe
159
Changes in what are altering the structure and function of many ecosystems
temperature and precipitation
