midterm 1 Flashcards
(162 cards)
1
Q
evolution
A
the change over time in the genetic composition of pops
2
Q
5 mechanisms that can change allele and genotypic freqs
A
- natural selection
- mutations
- genetic drift
- gene flow
- non-random mating (not allele freq, only genotypic)
3
Q
how do you calc allele freqs
A
of copies of allele/total # of alleles in pop
4
Q
5 hardy-weinberg conditions
A
- no selection
- no mutation
- no migration
- no genetic drift (infinitely large)
- random mating
5
Q
hardy-weinberg eqtn
A
p^2 + 2pq + q^2 = 1
6
Q
how do you determine if something is significantly different?
A
chi ^2 test
IF THE VALUE OF P IS LESS THAN 0.05, THEN THE POP IS NOT IN HW EQ
7
Q
mutation
A
spontaneous change in DNA
8
Q
mutation (4)
A
- random chance
- creates new alleles
- rates very low
- neutral pr deletrious
9
Q
mutation (4)
A
- random chance
- creates new alleles
- rates very low
- neutral or deleterious
10
Q
orgs with the highest rate of mutation
A
viruses
11
Q
why do viruses have the highest rate of mutation?
A
reverse transcription w/ RNA; it’s much less stable and no check stage
12
Q
gene flow
A
individuals move into a pop
13
Q
gene flow and alleles
A
adds new ones or changes the freq of alleles already present
14
Q
gene flow
A
individuals move into a pop; homogenizes
15
Q
gene flow and alleles
A
adds new ones or changes the freq of alleles already present
16
Q
natural selection
A
non random process/event w/ differential qualities to survival and repro
17
Q
what does n.s. lead to
A
adaptation
18
Q
who coined n.s.
A
darwin
19
Q
adaptation
A
adjustment/changes to an org that allows it to become more suited to their env
20
Q
when does n.s. lead to evo?
A
if genotypes differ in avg fitness then some will contribute more alleles to future generations
21
Q
fitness
A
the relative repro ability of an individual
22
Q
stabilizing selection
A
selects against the extremes
23
Q
directional selection
A
selects against one of the 2 extremes
24
Q
disruptive selection
A
selects against the mean
25
which type of selection can lead to speciation?
disruptive
26
genetic drift (3)
1. change to allele freqs by chance alone
2. some individuals, by chance, leave behind more offspring
3. small pops more prone
27
2 types of genetic drift
1. founder effect
| 2. pop bottleneck
28
founder effect
small group leaves a large pop and starts a new pop
29
pop bottleneck
large pop shrinks to a small # of individuals, which reproduce to repopulate
30
founder effect and alleles
allele freqs in small pop could be diff from large pop and this migration could result in loss of alleles
31
pop bottleneck and alleles
resulting gene pool may no longer be reflective of the original pop; by chance alone, certain alleles may be changed or lost
32
pop bottleneck and alleles
resulting gene pool may no longer be reflective of the original pop; by chance alone, certain alleles may be changed or lost
33
genetic drift can cause harmful alleles
to become fixed in the pop
34
over time, genetic drift can (2)
1. lead to changes of alleles
| 2. lead to loss of alleles
35
does non-random mating change allele freq?
no
36
mutation introduces new alleles. what is it's affect on diversity?
inc div w/in and btwn pops
37
geneflow/migration introduces new alleles. what is it's affect of diversity?
inc div w/in pops, decs div btwn pops
38
genetic drift results in a loss of alleles. what is it's affect on diversity?
dec div w/in pops, inc div btwn pops
39
natural selection removes harmful alleles. what is it's affect on diversity?
usually dec div w/in pops, can inc or dec diversity btwn pops
40
when would n.s. dec diversity btwn pops?
if in same env
41
when would n.s. inc diversity btwn pops?
if in diff envs
42
mating
combines alleles into genotypes
43
2 types of non-random mating
1. assortative
| 2. disassortative
44
asssortative mating
mates are genetically/phenotypically similar (eg. inbreeding)
45
dissassortative mating
mates are genetically/phenotypically diff
46
assortative mating leads to an excess of
homozygotes
47
if assortative mating occurs over many generations this could lead to
potential speciation
48
disassortative mating leads to an excess of
heretozygotes
49
speciation
formation of new species
50
allopatry
living in diff areas
51
sympatry
living in the same area
52
2 types of speciation
allopatric and sympatric
53
3 steps of speciation
1. isolation
2. divergence
3. repro isolation
54
isolation
geographic separation prevents gene flow
55
divergence
after isolation -> no gene flow -> pops can diverge -> mainly by genetic drift
56
divergence and mutations
muts accumulate separately in each pop
57
divergence in small pops
most likely by genetic drift
58
repro isolation
after divergence in isolation, 2 pops may no longer be able to prod viable fertile offspring
59
2 types of repro isolation
1. prezygotic repro isolation
| 2. postzygotic repro isolation
60
preozygotic repro isolation
hybrid mating doesn't occur
61
postzygotic repro isolation
hybrid offspring are unfit/sterile
62
repro isolation in 2ndary contact
after divergence in isolation, pops come back together in hybrid zones -> offspring are unfit if prod
63
reinforcement
n.s. for avoiding hybrid mating; completes reproductive isolation
64
sympatric speciation
2 groups in the same place; isolation by biology rather than geo
65
dispurtive selection can lead to which type of speciation?
sympatric (habitat preferences)
66
disruptive selection + isolation =
sympatric speciation
67
what else can cause isolation?
chromosomal changes including polyploidy
68
polyploidy
the presence of extra sets (more than 2) of chromosomes due to accidents during cell division
69
instantaneous speciation
when matings become incompatible in a single generation
70
2 types of polyploidy
1. autopolyploid
| 2. allopolyploid
71
autopolyploid
when a species doubles its chromosome number due to an error in meiosis -> nondisjunction -> 4n
72
what happens to the autopolyploid organism
becomes repro isolated from diploid parents
73
allopolyploid
results from hybridization btwn 2 species
74
allopolyploid and meiosis
autopolyploid 4n undergoes meiosis again and prod 2 diploid gametes/a new species
75
evolutionary independence
gene flow is low enough that species can diverge
76
morphological species concept
based on similarities in morphological features
77
biological species concept
must incl repro isolation -> failure to prod fertile hybrid offspring (not applicable to plants)
78
phylogenetic species concept
using phylogeny to determine evolutionary independence
79
3 ways to distinguish a species
1. morphological species concept
2. biological species concept
3. phylogenetic species concept
80
monophyly
all living descendants of a common ancestor
81
monophyletic group
common ancestor and all its descendants (clade)
82
paraphyletic group
common ancestor and some BUT NOT ALL descendants -> EXCLUSION
83
polyphyletic group
two or more ancestors, descendants -> CONVERGENT EVOLUTION
84
phylogeny
pattern and timing of evolutionary branching events
85
sister taxa/groups
2 groups that are each other's closest relatives
86
phylogenies are
inferred from morphological and molecular data
87
homology
similarity of traits DUE TO SHARED COMMON ANCESTRY
88
analogy
similarity of traits not due to common ancestry but due to CONVERGENT EVO
89
convergent evolution
similar env pressures produce similar (analogous) adaptations in organisms from diff evolutionary lineages
90
homology
related species should have traits in common, inherited from their common ancestor
91
shared derived
modified form of the trait that is unique to that group
92
shared ancestral
form of the train in the ancestor of the group
93
outgroup
ancestral to what you're studying; tells you if traits are ancestral or derived
94
synapomorphy
a characteristic present in an ancestral species and shared exclusively (in more or less modified form) by its evolutionary descendants
95
reversal
reversal of a trait to its ancestral state via mutation; opp of convergent evo
96
orthologous genes
found in a single copy in the genome and they diverge after speciation, but the gene's main function is conserved; a product of speciation
97
paralogous genes
result from gene duplication; are found in multiple copies in the genome and can evolve new functions; w/in a species
98
binomial nomenclature
genus, species (species name should be italicized) L.
99
order of the hierarchical level of classification
1. domain
2. kingdom
3. phylum
4. class
5. family
6. genus
7. species
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100
cyanobac comprise how much of the global living biomass?
48%
101
cyanobac play key roles in which 3 cycles of the biosphere?
O, N, C
102
what characteristic made cyanobac able to shape the course of evo and eco change throughout eths history?
photoautotrophic
103
stromatolite makeup
layers are minerals and sediment ppttn from the saltw which was trapped w/in the sticky layer of mucilage that surrounds cyanobacterial colonies
104
o2 fluctuation
1st rise started w/ cyanobac; depends on the presence/abundance of plants and free O2 being soaked up in the ocean
105
cyanobac can fix nitrogen for
plants, coral reefs
106
cyanobac and the O2 cycle
prod 1/2 the photosynth of the open ocean; 20% of the atmospheric O2
107
cyanobac + fungi =
lichens, also soil crusts?
108
cyano repro
asexually by binary fission and fragmentation
109
how many chromosomes do cyanobac have?
1 circular
110
how quickly can cyanobac repro?
20-30 mins
111
hormogonia
motile filaments involved in fragmentation in cyanobac
112
fragmentation
hormogonia break down into small pieces and become new colonies
113
cyanobac blooms suffocate plants. how do they stay afloat?
air vesicles
114
cyanotoxins
toxins secreted by cyanobac that can cause death
115
2 mechanisms for generating genetic div in cyanobac
1. mutation rates higher due to their fast repro time
| 2. horiz gene transfer
116
DNA from diff cyanobac cells can be brought together by (3)
1. conjugation
2. transformation
3. transduction
117
conjugation
DNA transferred btwn cells via a sex pilus
118
transformation
free DNA absorbed
119
transduction
DNA transferred via viruses
120
cyanobac's photosynthetic pigments
chlorophyll a
carotenoids
phycobilins
121
cyanobac became the chloroplast of euk cells through what mechanism
endosymbiosis
122
why do you see the colours that you see?
they are not absorbed by the object/org
123
chloroxybacteria
a unique group of cyanobac containing chlorophyll a and b and no phycobilins, similar to green algae and plants
124
carboxysomes
micro-compartments surrounded by a pro shell filled with RuBisCo
125
carboxysomes function
provide a compartment for RuBisCo to bond only with CO2 in
126
cyanobac unicellular shapes (2)
rods
| spherical
127
cyanobac colonies shapes (3)
filaments (branched/unbranched)
sheet-like
hollow balls
128
why are cyanobac colonies surrounded by a mucilagenous sheath? (3)
protection
holding cells together
movement
129
advantages to living in a colony (3)
1. division of labour; cells become specialized which can create
2. diversification of niches
3. protection
130
heterocyst
specialized N fixing cell that creates a micro-anaerobic env to avoid having nitrogenase inactivated by O2
131
heterocyst structure
3 membraned cell
132
akinetes structure
large thick-walled dormant cells
133
akinetes function
wait out bad times -> store food?
134
when would you expect a cyanobac bloom?
late spring
135
euk cells vs prok cells
euks are membrane-bound organelles and more complex than proks
136
5 unifying characteristics shared by all euks
1. multiple linear chromosomes
2. mitochondria -> ATP
3. rough and smooth ER/Golgi
4. cytoskeleton (microfilaments/microtubules)
5. 18s vs 16s rRNA
137
protists are (3)
1. single celled (some form colonies)
2. euks
3. microscopic (except seaweed)
138
plankton
free-floating unicellular orgs, cannot go against current
139
phytoplankton
photosynth plankton
140
photoautotrophic protists
able to do photosynth; cyanophora
141
heterotrophic protists
need to ingest food particles; giardia intestinalis
142
saprotrophic protists
decompose and absorb org molecs; physarum
143
mixotrophic protists
combine photosynthesis w/ ingestion of prey; euglena gracilis
144
protists engulf things via
phagocytosis
145
symbiosis
a relationship btwn 2 or more orgs
146
mutualism
benefits both species; zooxanthellae in sea slug
147
commensalism
benefits 1 while the other is indifferent; red algae epiphyte on Ulva
148
parasitism
benefit one species and harms the other; phytophthora infestans on potatoes
149
asexual repro occurs when conditions are
favourable
150
sexual repro occurs when conditions are
unfavourable -> might create new genes that can help
151
why are protists paraphyletic
they include some but not all descendants of their most recent common ancestor
152
endosymbiosis
the process in which one cell is engulfed by another and retained internally, such that the 2 cells live together and integrate, perhaps permanently
153
which 2 organelles evolved through endosymbiosis
(1)mitochondria, chloroplast
154
4 points supporting endosym in protist evolution
1. both mito and chloro retain their own DNA which is circular and small; seqs similar to bacteria
2. mito and chloro ribosomes are more simlar to bacterials
3. mito and chloro have double membrane envelopes
4. mito and chloro repro by binary fission; nucleus doesn't control when the cells /
155
where do membranes 1 2 and 3 come from
1. phagocytosis
| 2. and 3. cyanobacteria
156
why do cyanobac have 2 membranes?
b/c they're gram -ive
157
4 membranes in red agla endosymbiosis
outside in
1. plasma of euk
2. red alga
3. 4. cyanobac
158
apicoplasts
a relict, non photo plastid BUT vital
159
tertiary endosymbiosis
phagocytosis of a crypotomonad w/ 2ndary plastid by a dinoflagellate
160
when do cellular slime molds aggregate?
when food is unavailable, they aggregate to form a single multicellular body called a pseudoplasmodium
161
cAMP
cyclic mononucleotide of adenosine that is formed from ATP and is responsible for the intracellular mediation of hormonal effects on various cellular processes.
162
altruism in slime molds
- 20% of the cells sacrifice themselves to become the stalk and the remaining cells become spores
- sacrificing yourself for the greater good of your species BECAUSE YOU WOULD NOT SURVIVE ON YOUR OWN
