exam 3 keiser Flashcards
(143 cards)
1
Q
what is evolution
A
change in the genetic compostiion of populations over time/alelle frequencies across generation
2
Q
Evolutionary theory
A
how and why evolution occurs
3
Q
Evolutionary theory
A
how and why evolution occurs
4
Q
foundations of evolutions
A
variation, natural selection, heritability, genetic drift, common ancestors
5
Q
variation
A
genotypes influence different phenotypes
6
Q
heritability
A
phenotypes are passed down from parents to offspring via genes
6
Q
heritability
A
phenotypes are passed down from parents to offspring via genes
7
Q
genetic drift
A
more variation can arise through mutations
8
Q
decesent with modifcation
A
charles darwin and lyell’s theory about evolution
9
Q
endemic species
A
exist in only one location
10
Q
alfred wallace
A
co founder of evolution, mostly known for biogeography
11
Q
evolutionary synthesis
A
happened afte rhte discovery of mendelian genetics, reconciled evolution and genetics (1950s)
12
Q
fitness
A
: the sucess of a pheontype regarding survival and reproductive capability RELATIVE TO OTHER PHENOTYPES
13
Q
adaption
A
beneficial trait that spreads through a population by natural selection (also the process that produces it)
14
Q
what generates variation
A
mutation and migration
15
Q
what reduces variation (sometimes)
A
selection and nonrandom mating
16
Q
mutations
A
changes in nucleotide sequences taht occur in individuals
17
Q
genetic drift
A
small changes in allele freuence that produce large changes over time
18
Q
when is genetic drift most effect
A
in small popualtions, with neutral mutations over time
19
Q
allele frequency
A
the proportion of each allele in the “gene pool”
20
Q
what does at allele frequence of 1.0 / 0.5/ 0 mean?
A
1.0 - everyone has this allele (fixation)
0.5 = half of the population has this allele
0 = no one has this allele
21
Q
population bottlenecks
A
caused by extreme declines in populaiton size, reducing genetic variation in the survivng population (elephant seals)
22
Q
founder effects
A
initiation of a new population with fewer individuals, reducing variation in the survivng population
23
Q
migration
A
movemnet of alleles from one population to another, increased variations (gene flow)
24
selection
reduces variation sometimes (natural selection reduces individuals with deleterious allelles
25
what is selection usually represented by
frequency distributions
26
frequency distributiosn
vizualize count data, can show absolute frequences or relative frequences, like proportions or percentages
27
sexual selection
when individuals choose partners based on thier charactersitics (can lead to things like long tails, colorations)
28
modes of selection
directional, disruptive, stablizing
29
direction selection
more colorful moths are eat by birds, grey moths survive and reproduce
30
stabilizing selection
when individuals closest to the mean have the highest fitness, reduces variation but doesnt change the man (purifying selection)
31
disruptive selection
increaes variation can generate polymorphisms
32
polymorphisms
stable, discrete categories of pheotypes - smaller beaked birds have an advantage (can eat small seeds) big beaked birds have an advantage (can crack big seeds), medium beaked birds have it rough
33
heterozygote advantage
in changing condiitons, heterozygous indivs outperform homozygotes, which helps maintain allele variety.
34
Geographic variation
genetic variation is maintained in populatiosn in different geographic regions with different selective pressures
35
Frequence dependent selection
maintains genetic variations - polymorphisms can be maintained when its fitness is determined by its frequencey (scale eating fish, the rarer type will always have less competitions)
36
artifical selection
purposefully guided by humans with a goal in mind
37
agricultural research
long term selection experiemnts showed that selection can result in strong phenotypic differences and that trait change can be reversed
38
what does artificial selection need to function
existing genetic variation
39
heritability
estimates the proportion of variation in a trait determined by inherited genes and the enviornment
40
what does it mean if H^2 = 1
All variation in a population is due to genetic differences
41
what does it mean if H^2 = 0
no genetic varioan; all variaiton in the population comes from differences in the enviornments experiences by the individuals
42
equation for hertiability
variation inherited / (vinherited + venviornment)
43
what is heritability not
its is not genetic determination
44
factors that affect heritability
precision of measurement, enviornmental change, migration/gene flow, inbreeding
45
the higher the heritability estimate -
the easier it may be to modify that trait via artificial selection
46
The breeders equation
a foundation toool in quantitiative genetis, used to prdict evolutionary change - R = h^2S (h^2 = heritability, s = selection differential, R = response to selection)
47
what does the breeder's equation assume
the trait of interest is not correlated with other traits affecting fitness
48
population genetic structures
can be described by frequences (0-1) of alleles and genotypes
49
formula of allele frequency
p = 2NAA + NAa = 2N (same with aa for the recessive)
50
p+q
ALWAYS 1
51
fixed
p = 1, q = 0 (or vice versa)
52
Hardy-Weinberg equilibrium
conditions for populaiton allele frequencies to stay the same
53
what are the 5 conditions for hardy weinberg equilibrium
no mutation, no selection, no gene flow, population size is infinite, and mating is random
54
how quickly can you restore HW equilibrium
one generation
55
what do deviations from HWE show?
that evolution is occuring
56
trade-offs in sexual selection
more likely to reproduce, but less likely to survive
57
2 main forms of sexual selection
intrasexual competition, mate choice
58
good genes hypothesis
some traits are honest signals of mate quality
59
runaway sexual selection
offspring will inherit their parent's ornamental traits and preferences for that trait
60
genetic (sexual) conflict
when genes that govern males and female traits are anatgonistic
61
mutations
novel gene combos
62
nucleotide substitutions
changes in one nucleotide in a DNA sequence
63
synonymous substitutions
do not affect the function of a protein - neutral
64
nonsynonymous substitution
affect protein function, can ve deleterious, neutral or advantageous
65
hybrid incompability
offspring ofspring of individuals from different populations or even species are worse off
66
where are rates of substitution higher?
at synonymous sites vs non synonymous sits
67
neutral theory of molecular evolution
majority of evolutionary changes occursa t the molecular level and most genetic variation is due to random genetic drift of alleles that are selectively neutral
68
although genetic drift of exist gene variants is stronger in small populations
the rate of fixation of new neutral mutations is independent of population size
69
molecular clock
the rae of fixation of new neutral mutions is relatively constant, so it can be used as a molecular clock to calculate evolutionary diverengce times between species
70
dn
of nonsynonymous substitutiosn per non synonymous site
71
ds
numbers of synonymous substitutions per synonymous site
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dn/ds = 1
neutral
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dn/ds > 1
positive directional selection
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dn/ds < 1
stabilizing selection
75
gene expression
might account for mucch of the evolution of diverse body forms we observe across living organisms
76
homeotic mutations
replaces one structure with another
77
genetic switches
can turn genes on or off, regulate gene expression
78
heterometry
different amount of gene expression
79
heterochrony
different timing of gene expression
80
heterotropy
spatial diference in difference in gene expression
81
phylogeny
evolutionary history of genetic relationships
82
phylogenetic tree
visual reconstruction of shared history
83
lineage
series of ancestor and descendant populations
84
components of a phylogenetic tree
vertical distances between branches have no meaning, order after a node is arbitrary
85
nodes
indicate timing of splitting events
86
split events
a speciation event, gene dupliction, transmission event etc
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homologous features
shared by two or more species and inherited fro m a common ancestor
88
ingroup
the group of organisms of primary interest
89
outgroup
species closely related to by phylogenetically outside of the group of interst
90
parsimony
the preferred explanation of observed data is the simplest explanation
91
convergent evolution
different selective pressures on different taxa led to similar traits
92
Taxa
expected to be monophyletic - can be cut off from a phlyogenetic tree witha s ingle cut in the tree
93
polyphyletic groups
do not include its common ancestory - birds and mammals are warm blooded, but it doesnt inlcude their common ancestors
94
paraphyletic
do no include all the decsendants of a common group - reptiles inlcudes turtles, snakes etc, ut not birds even through they are within that lineage
95
how is a molecular clock calibrated
the fossil record, known times of divergence, biogeographic data
96
species
groups of organisms that share genetic and morphological attributes, and are reproductively isolate from other such
97
speciation
Divergence of biological lineages and emergence of reproductive isolation
98
what did linneaus base the taxonomic system off
appearance / morphological concept
99
polymorphisms
multipe phenotypes within one species
100
cryptic species
two or more species that are indistinguisable
101
biological species concept
species are groups of actually or potentially interbreeding natural poplaitons that re reproductively isolaed from other such groups
102
reproductive isolation
two groups can not make viable offspring
103
complications with biological species conept
asexual reproduction, extinct groups only known from fossils, hybridization between closely related species
104
phylogenetic / lineage species concept
a species is a branch on a phylogeny which ahs a history that starts at a species event and ends at another speciation or extinction
105
Dobzhansky Muller model
genetic basis for disruptiv selection which leads to speciation
106
hybrid incompatibility
two species interbreed but their offspring are bad at surviving so they eventually stop breeding wth each other
107
hybrid zones
when reproductive isolation is incomplete
108
what maintains species barriers
hybrid suffering
109
do hybrid zones always reinforce species barriers
no, sometimes they can relax barrier and act as a bridge between species
110
allopatric speciation
speciation that results when a pop is divided by a physical barrier
111
sympatric speciaiton
no physical isolation, occurs within the same population
112
sister species
species that are each others closeset relatives can arise on opposite sides of the barrier
113
ecological speciation
divergent natural selection ebtween contransting ecological enviornemnt
114
ecological speciation
divergent natural selection ebtween contransting ecological enviornments
115
polyploidy
the duplication of sets of chromosomes within indivs, can result in complete reproductive idolation in 2 generations
116
temporal isolation
changes in breeding season can cause reproductive isolation
117
behavioral isolation
mating and stuff are different
118
adaptive radiation
rapid diversification of a large number of descendant species from a single ancestor species that now inhabit a variety of enviornments
119
who has high speciation rates
groups with poor dispersal abilites, and lineages with strong sexual selection
120
stratigraphy
the study of geological strata - the oldest rocks on the bottom strata and the new rocks on top
121
radioisotopes
decay in a predictable pattern over long period of time
122
half-life
half of the atoms in a radioisotope decay to become a different, stable (nonradioactive) isotope
123
radiometric dating
the use of radiosotopes to date fossils and rocks is known as radiometric dating
124
paleontology
extinct life
125
3 time periods to know
archean cambrian creataceous
126
continental drift
the movement of continents due to plate tectonics
127
plate tectonics
geophysical movements of the "plates that make up the Earth's layer
128
pangea
big ass continenet
129
mass extintictions
things like meteors, sea level
130
atmospheric changes
atmosphere did not have much oxygen until cyanobacteria came on the scene
131
more oxygen
big ass bugs
132
permineralization
occurs when an organism is buried in sediment and empty spaces are filled with minerals
133
holotype
a single physical speciment used to describe a species
134
casts and molds
the organisms dissolves and leaves an organism shaped hole
135
impressions
trace fossil that hint at an extinct organisms biological activity but don't contain any organic material
136
abiogenisis
origin of life, RNA first hypothesis
137
Miller - Urey Experiment
tested the chemical origin of life hypothesis and produced ovr 20 amino acids from chemicals and electricity
138
cambrian explosion
glaciers recede, increasing o2, and huge explosion of biological diversity
139
mass extinctions
end of ordovician -> glaciers formed and oceans receded and 75% of things died
140
permian
pangea, and at th end there were massive volcanic eruptions that cooled the climate and then created a glaciation event - 96% of all multicellular species became extinct at the end of the permian
141
KT extinction
at the end of the cretaceous period, meteor struck in mexico and killed alll non - avian dinosuars plant life died too
142
hominin evolution
bipedal locomotion, split off from chimpanezees
