unit 1: evolution Flashcards
1
Q
living species show
A
common ancestry
2
Q
do individuals evolve?
A
no, populations evolve
3
Q
geographic distribution of living organisms
A
biogeography
4
Q
change in the frequency of alleles in a population
A
evolution
5
Q
loss of all variants except one
A
fixation
6
Q
traits whose similarities are explained through common ancestry
A
homology
7
Q
tendency for genetic variants that enhance fitness to go to fixation
A
natural selection
8
Q
existence of multiple variants within a population
A
polymorphism
9
Q
fossil taxa that have some of the derived traits of a living group
A
transitional fossil
10
Q
hierarchical nesting of biological taxa
A
classification
11
Q
type of reproduction that yields a tree for
A
asexual reproduction
12
Q
homogenizes populations
A
sex
13
Q
glues local populations together
A
gene flow
14
Q
lineages isolated for long enough
A
lose ability to interbreed (speciation)
15
Q
all the descendants of an ancestral lineage
A
clade
16
Q
represents lineage splitting
A
node
17
Q
remove tips or clades from tree without changing the topology
A
pruning
18
Q
list of all clades in a tree
A
topology
19
Q
biological classifications
A
taxonomy
20
Q
if there are multiple hypotheses, the most likely is the most simple
A
parsimony
21
Q
same trait develops separately in 1 or more lineages
A
convergent evolution
22
Q
trait lost and never reevolves
A
reversal
23
Q
recency of common ancestor
A
relatedness
24
Q
are all living species equally evolved?
A
yes
25
unethical attempts to increaser the frequency of desirable traits
eugenics
26
no change in underlying heritable traits
phenotype plasticity
27
particular variant of a gene
allele
28
place in genome where alleles are encoded
locus
29
majority of traits are
continuous
30
more than one allele at given locus
polymorphic
31
no new alleles, mating is random, all alleles equally fit, population is infinitely large
harvey weinburg assumptions
32
2pq
equation for frequency of heterozygote
33
gains and losses are
equally likely
34
changed caused by the environment leads to
plasticity
35
allele that enhances fitness
beneficial mutation
36
allele that decreases fitness
deleterious mutation
37
selection that arises when one allele consistently raises fitness, beneficial allele will be fixed eventually
directional selection
38
most traits are
genetically complex
39
in haploids, allele frequency equals
genotype frequency
40
x+y/2 =
frequency of A1
41
z+y/2 =
frequency of A2
42
occurs when genotypes differ in fitness
directional selection
43
average number of offspring produced by one genotype relative to another
relative fitness
44
violates assumption that populations are infinitely large, allele frequency always changing
genetic drift
45
population lineage shrinks to small size for a period, decreasing variation
genetic bottleneck
46
genetic drift only overpowers directional selection if
small allele frequency and small population
47
frequency of deleterious alleles that have accumulated in a population
genetic load
48
compare homozygote to other homozygote (compare offspring or reproductive ability)
relative fitness
49
explains adaptive change
directional selection
50
when no genetic variation
evolution stops
51
the rate of mutations is independent of
need
52
when differing fitness, causes fixation of favored, variation replaced by mutation
directional selection
53
probability that an allele is fixed under drift is
equal to its frequency
54
genetic drift means
small populations have less genetic variation and are vulnerable to pathogens
55
result in genetic disorders
deleterious alleles
56
influenced by mutation rate and strength of selection
frequency of a disease
57
tend to have higher prevalence because mutant alleles can hide in carriers
recessive disease alleles
58
expected frequency of dominant lethal alleles is equal to
mutation rate
59
can result in different frequencies of disorders
genetic drift
60
heterozygotes have highest fitness, conserves both alleles in a population
overdominant selection
61
both alleles preserved
polymorphism
62
extent to which variation in a continuous trait has a genetic basis
heritability
63
is all variation heritable
no, there is a mix of genetic and environmental variation
64
mean of reproducing individuals minus mean of whole population
strength of selection (s)
65
mean of offspring generation minus mean of parent population
response to selection (r)
66
heritability
h^2
67
breeders EQ
r = h^2 x s
68
individual who is heterozygous for disease
carrier
69
selection in which heterozygote has lowest fitness
underdominant selection
70
alleles shared between closely related species
trans-species polymorphisms
71
selection that favors trait values at the extremes
disruptive selection
72
shape of distribution when disruptive selection and assortative mating
bimodal
73
selection that disfavors extremes, favors average individual
stabilizing selection
74
complex traits
multiple coordinated components
75
dramatic traits in an organism that decrease and organisms variability but evolve because they are favored by sexual selection
exaggerated secondary sexual selection
76
secondary sexual characteristics become exaggerated due to feedback between male traits and female preferences
runaway sexual selection
77
movement to breed for desirable traits, unethical
eugenics
78
does heritability tells us about differences between groups
no
79
occurs when fitness is highest near the middle of the distribution (common when on stable adaptive peak)
stabilizing selection
80
reduces trait variation
stabilizing selection
81
increases trait variation
disruptive selection
82
traits that reduce individual ability to survive, caused by
sexual selection
83
fitness gain from mating outweighs fitness cost for survival
sexual selection
84
speciation driven by geographic isolation
allopatric speciation
85
phenomenon in which individual organisms tend to mate with other organisms with traits like theirs
assortative mating
86
species defined by ability of members to reproduce and interbreed
biological species concept
87
gradual changes in traits as a function of geo separation
clinal variation
88
genetic variation among geo separated populations where each population contains genetically similar individuals
discrete variation
89
2 organisms no longer able to reproduce
intrinsic reproductive isolation
90
view that species are defined by clades
phylogenetic species concept
91
splitting of ancestral species into distinct species
speciation
92
speciation without geographic isolation, RARE, driven by assortative mating
sympatric speciation
93
females choose desirable males and have desirable sons, increasing fitness
female choosiness, leads to sexual dimorphism
94
species are populations, applies only to sexual taxa
biological species concept
95
species are taxa, products of evolution
phylogenetic species concept
96
subspecific groups need to be genetically distinct
subspecies on tree
97
focuses on the evolution of reproductive incompatibility
speciation biology
98
if a mutation decreases reproductive ability
the allele is selected against
99
trait that is beneficial in a species for one function but originated to fulfill a different function
expatation
100
evidence that all cellular life shares common ancestry
proteins, L amino acids, genetic molecules, genetic system, metabolic system
101
reduction of CO2 to organic molecules using light energy, no O2 released
anoxygenic photosynthesis
102
theory that mitochondria and nucleus both evolved within the same eukaryotic lineage
autogenous hypothesis for eukaryotes
103
clade of bacteria characterized by ability to perform oxygenic photosynthesis
cyanobacteria
104
phenomenon in which prokaryotic cell comes to live and divide within a host cell
endosymbiosis
105
theory that mitochondria are derived from endosymbiotic bacteria taken up by host cells whose genome is found in the eukaryotic nucleus
endosymbiotic hypothesis for eukaryotes
106
cells with outer membrane and internal membrane bound organelles
eukaryotes
107
theory for development of eukaryote internal compartments that suggests outer plasma membrane or prokaryote ancestor was pushed outward
inside out theory
108
most recent common ancestor of all life
LUCA
109
theory for the development of eukaryotes that starts with production of vesicles within cytoplasm by internalization
outside in theory
110
reduction of CO2 to organic molecules using light energy in which water is the electron donor, 02 gas released
oxygenic photosynthesis
111
cells with an outer membrane containing no internal membrane structures
prokaryotes
112
rapid expansions of clades to give rise to many diverse species adapted to different ecological niches
adaptive radiations
113
a clade of tetrapods characterized by an egg that can persist on dry land, complex lungs, protective skin
amniotes
114
a clade characterized by exoskeletons
arthropods
115
specialized filter feeding structures found in whales
baleen
116
trait of having a single plane of symmetry
bilateral symmetry
117
first period of the paleozoic era, rapid radiation of bilaterians
cambrian period
118
cycle of measures and countermeasures between interacting lineages
evolutionary arms race
119
trait that allows a lineage to occupy a new niche
key innovation
120
clade of eukaryotes characterized by flagellum
opisthokont clade
121
traits in a lineage that existed prior to a transition that give that lineage some advantage in a new ecological niche
pre adaptations
122
rapid expansions of clades to give rise to many species
radiations
123
idea that populations must keep adapting via directional selection because other species with which they interact are also constantly evolving
red queen principle
124
clade of vertabrates characterized by four limbs and lungs
tetrapods
125
theories to explain how life developed
self replicating RNA, protocell, surface associated chemical ecosystem
126
was there life before LUCA
yes
127
how do prokaryotic archaea differ from bacteria
membrane chemistry, genetic systems (similar to euks)
128
only cells that can do oxygenic photosynthesis
cyanobacteria
129
more cells in humans are
bacteria
130
ozone layer built up, high oxygen levels, chemical env of earth changes
results of cyanobacteria
131
mitochondria derived from
alpha proteobacteria
132
chloroplasts (plastids) derived from
cyanobacteria
133
two competing theories for mitochondria
endosymbiotic (own genome) and autogenous
134
merger of bacterial and archaeal lineages
eukaryotes
135
oxygenic photosynthesis, invasion of land, agriculture and tech
evolutionary events that changed the planet
136
adapted to tree climbing, mainly eat fruit
arthropoids
137
are modern chimpanzees the ancestors of humans
no, they share a common ancestor
138
apes remained in forested adaptive zones, resulting in
stabilizing selection
139
homonins (human ancestors) transition to more open grassy environments, resulting in
directional selection
140
hypotheses for the evolution of bipedal movement
looking for predators or prey, carrying stuff and throwing, more efficient
141
gradual shift to meat eating then hunting using rocks
scavenger hypothesis
142
resulted in sweat glands, lighter frame, longer legs, less hair
hunting in daytime african savanna
143
selected for overarm throwing (result of clasping hands, binocular vision, shoulder flexibility)
hunting
144
required technological and social coordination, led to tools, larger brain, true language
hunting
145
face muscles, white eyes, laughing, crying, democracy
physical and behavioral traits of humans
146
technology and teamwork led to
homonin migration
147
recent spread of humans explains why
genetically homogeneous and why genetic diversity decreases with distance from africa
148
is the homonin clade tree like
no, very complex evolution
149
Fst
measure of genetic differentiation between populations
150
why does reproductive isolation not typically evolve within a single population?
Because individuals that cannot mate with other members of their population generally have lower fitness
151
What is the most important role of geographical isolation in allopatric speciation?
The splitting of the ancestral population into geographically isolated regions prevents them from exchanging genes
152
What provides the best evidence of universal common ancestry?
Traits that are not obviously essential or optimal yet they are still shared by all cellular life
153
how long ago did life originate on Earth?
4 Ga
154
what were important effects of oxygenic photosynthesis?
The accumulation of ozone which shielded the earth from ultraviolet light and helped make land more easily colonized, The "rusting" of the oceans as dissolved Fe(II) was oxidized into reddish Fe(III), A change to the atmosphere that allowed for the evolution of large aerobically respiring species such as eukaryotes
155
What character is was NOT likely to be present in LUCA, the last universal common ancestor?
Aerobic respiration
156
What is the difference between oxygenic photosynthesis (OP) and anoxygenic photosynthesis (AP)?
In OP oxygen in H2O is the electron donor; in AP H2S is the electron donor
157
responsible for cycling of elements such as C, N, S, and Fe
bacteria
158
Where does the nucleus come from under the outside in model
Internalization of the plasma membrane
159
Where does the nucleus come from under the inside-out model?
The original cell, which became surrounded by the cytoplasm
160
What about the recently discovered Asgard archaea, the closest relatives of eukaryotes so-far discovered, supports the inside-out theory
The cell have extracellular protrusions that interact with ectosymbiotic prokaryotes
161
What trait(s) differentiates humans from other great apes
bipedality, knee locking, twisted upper arm
162
About when did anatomically modern humans migrate out of Africa
100 Ka
163
sexually dimorphic means likely
polygamy
164
Which is the best explanation for why exaggerated secondary sexual characteristics are more common in males than females
Because males often differ greatly in mating success, selection more strongly favors traits that improve mating success (even if they lower survival)
165
What does an internode on a phylogenetic tree represent
A set of local populations linked together by enough gene flow that they tend to remain genetically similar
166
What does a node on a phylogenetic tree represent?
When the descendant lineages first became genetically isolated, splitting of ancestral population lineages, and last common ancestor of the clade
167
all the descendants of a particular ancestral lineage
clade
168
The rate at which a particular kind of mutation occurs is independent of the fitness of the resulting allele
true
169
Is a change in the environment necessary for evolution by directional natural selection
no
170
explains why organisms tend to be well adapted, can only act on loci that have at least two alleles segregating, requires genotypes differ in fitness, non random
directional selection
171
What needs to apply for a trait in two species to be homologous
two traits are homologous if they derived from the same evolutionary origin
172
what type of disease allele occurs at the highest frequency (under directional selection)
large gene, recessive, mildly deleterious
173
Why does local inbreeding increase the incidence of genetic disorders
It lowers the population size, increasing the rate of genetic drift AND it leads to more homozygous individuals who will express recessive genetic disorders
174
eugenics fails to consider
environment
175
genetic drift can cause fixation of deleterious alleles, population might lose so much variation all are susceptible to same disease, beneficial alleles may be lost despite being favored
problems with small populations
176
