Exam 1 Flashcards
(126 cards)
1
Q
what is evolution?
A
change in the gene pool of a population over time
2
Q
what is genetic variation?
A
differences in DNA sequence between individuals in a population
3
Q
what is a species?
A
a group of individuals who are capable, through reproduction, of sharing alleles with one another
4
Q
what is a population?
A
groups of organisms of the same species living in the same geographical area
5
Q
what is a gene pool?
A
total of all the alleles present in all of the individuals in a population/species
6
Q
what is an allele?
A
version of a gene
7
Q
gene pool changes, even small ones are what?
A
evolution
8
Q
what are mutations?
A
random errors in DNA replication
9
Q
what is recombination?
A
switching of DNA between chromosomes
10
Q
what can cause genetic variation?
A
mutations and recombination
11
Q
what is the formula for allele frequency?
A
total # of alleles in population
12
Q
how many copies of an allele does a homozygote carry?
A
2
13
Q
how many copies of an allele does a heterozygote carry?
A
1
14
Q
how do you measure genetic variation?
A
allele frequencies
15
Q
what can you quantify by calculating the allele frequencies in a population?
A
genetic variation
16
Q
what are the 3 ways to measure genotype/allele frequency?
A
- observable traits
- gel electrophoresis
- DNA sequencing
17
Q
what are the difficulties of using observable traits to measure genotype/allele frequencies?
A
-traits are encoded by more than one gene
-effects of the environment on the phenotype
-only some genes have easily observable phenotypes
18
Q
what are the difficulties of using DNA sequencing to measure genotype/allele frequency?
A
expensive and time consuming
19
Q
what does the hardy-weinburg equilibrium predict?
A
predicts the allele and genotype frequencies in future generations of a population in the absence of evolution
20
Q
what are the conditions of the hardy-weinburg equilibrium?
A
- there can be no differences in the survival and reproductive success of individuals
- populations must not be added to or subtracted from by migration
- there can be no mutation
- the population must be sufficiently large to prevent sampling errors
- individuals must mate at random
21
Q
what is the hardy-weinburg equation?
A
p^2 + 2pq + q^2 = 1
22
Q
what does the p stand for in the hardy-weinburg equation?
A
frequency of A
23
Q
what does the q stand for in the hardy-weinburg equation?
A
frequency of a
24
Q
what does the p^2 stand for in the hardy-weinburg equation?
A
frequency of AA homozygous
25
what does the 2pq stand for in the hardy-weinburg equation?
frequency of Aa heterozygous
26
what does the q^2 stand for in the hardy-weinburg equation?
frequency of aa homozygous
27
what is the usefullness of hardy-weinburg equation?
-defines causes of evolution
-allows us to determine whether a population is experiencing evolution
28
If your actual numbers are different from your hardy-weinburg equation numbers...
population is not in hardy-weinburg equilibrium and evolution is occurring
29
if your actual numbers are the same as your hardy-weinburg equation numbers...
population is in hardy-weinburg equilibrium and evolution is not occurring
30
who came up with natural selection?
darwin and wallace
31
what are the conditions for natural selection to occur?
-must be variation for a trait within a population
-variation must be inheritable
-individuals with one version of the trait must produce more offspring than those with a different version of the trait
32
what is differential reproductive success?
individuals with one version of the trait must produce more offspring than those with a different version of the trait
33
what is adaption?
a trait that confers an advantage in survival/reproduction
34
what is fitness?
a measure of the extent to which the individuals genotype is represented in the next generation
35
natural selection increases overall ____ of the population
fitness
36
what is modern synthesis?
brings together mendelian genetics and darwinian evolution
37
what is positive selection?
natural selection that increases the frequency of a favorable allele
38
what is negative selection?
natural selection that decreases the frequency of a deleterious allele
39
what is balancing selection?
natural selection that keeps an allele ay an intermediate frequency in the population
40
what is heterozygote advantage?
occurs when a heterozygote has a highest fitness
41
what is directional selection?
occurs when one extreme of phenotypes is favored over the intermediate
42
what is disruptive selection?
occurs when both extremes do well
43
what is stabilizing selection?
favors the mean (ones in the middle)
44
what is artificial selection?
humans select for preferred traits
45
what is sexual selection?
selects for traits that increase mating success
46
what is intersexual selection?
1 male - 1 female, female chooses which male, males competing for female attention (doing dances to impress the female)
47
what is intrasexual selection?
1 male - multiple females, males compete with other males by fighting, if you win you get the girls
48
what is sexual dimorphism?
differences between males and females of a species
49
what does the outcome of natural selection depend on?
which trait is favored by the particular environment
50
what are the non-adaptive evolutionary mechanisms?
migration, mutation, genetic drift
51
what is gene flow?
movement of alleles between populations
52
what does migration result in?
populations becoming more similar over time
53
mutations create new ___?
alleles
54
____ errors are passed down to the next generation
mutation
55
what conditions make a population extremely vulnerable to genetic drift?
founder event, bottle neck
56
what is founder event?
a small # of individuals found a new population
57
what is bottleneck?
a large population is rapidly reduced in size
58
what is molecular evolution?
evolutionary past of a population will be reflected in the present population
59
what is genetic divergence?
the extent of genetic divergence is a function of time since isolation
60
what is the biological species concept?
species are groups of actually or potentially interbreeding populations that are reproductively isolated from other such groups
61
what are the limitations of biological species concept?
-difficult to observe
-doesn't work for asexual reproducing organisms
-doesn't work for extinct organisms
-judgement calls - hybrids or physically separated populations
62
what is morphospecies concept?
species are groups that look alike
63
what are the limitations of morphospecies concept?
-cryptic species
-sexual dimorphism - males and females have differences
-species with a large amount of variation in traits
-Judgment call
64
What is the ecological species concept?
Species are groups of organisms with the same niche
65
what is a niche?
The role a species plays in its environment
66
What is an example of a niche?
ladybugs that eat different leaves
67
What are the limitations of the ecological species concept?
-difficult to observe
-Judgment call
68
what is the phylogenetic species concept?
Species are groups of organisms that cluster together on a phylogenetic tree
69
what are the limitations of the phylogenetic species concept?
-Doesn’t work for extinct organisms
-Phylogeny is a hypothesis
-Judgment call
70
what is reproductive isolation?
Can’t reproduce because something is stopping them, Populations must be reproductively isolated to be considered separate species.
71
what is pre-zygotic isolation?
Isolation that happens before fertilization
72
what is post-zygotic isolation?
isolation happens after fertilization
73
what are the different types of pre-zygotic reproductive isolation?
-ecological/geographic isolation
-temporal isolation
-Behavioral isolation
-Mechanical/physical isolation
-gametic isolation
74
what does ecological/geographic isolation mean?
They live in different places
75
What does temporal isolation mean?
different time of mating
76
what does behavioral isolation mean?
They don’t respond to each other’s behavior
77
what does mechanical/physical isolation mean?
Physically cannot mate with each other
78
what does gametic isolation mean?
sperm and eggs mate with certain sperm and eggs
79
what are the types of post zygotic reproductive isolation?
Genetic incompatibility
80
What is speciation?
A population is split into two populations. Both have their own mutations
81
what is allopatric speciation?
Populations are separated by a geographic barrier, can be due to either dispersal or vicariance
82
what is adaptive radiation?
Many closely related species arise very quickly from a common ancestor
83
how does adaptive radiation happen?
Occurs when there is a little competition, happens after a mass extinction, disperse to an area with little species like them
84
what is Co speciation?
Speciation in one lineage for speciation in another lineage
85
what is an example of co speciation?
lice that can only live on gophers are forced to speciate if the gopher speciates
86
under the right circumstances, what can result from speciation?
adaptive radiation or co speciation
87
what is sympatric speciation?
speciation without geographic separation
88
how does sympatric speciation occur?
-very strong habitat preferences
-very strong mating preferences
-very strong disruptive selection
-polyploidy: plants - MOST COMMON
89
what is instantaneous speciation?
speciation that can happen "faster", in the span of 1 generation
90
what is polyploidy?
having more than 2 sets of chromosomes
91
what is an example of polyploidy?
4n, 6n, 8n
92
speciation can occur with or without ____, they often go together though
natural selection
93
natural selection may or may not lead to ______
speciation
94
what is speciation due to?
the accumulation of genetic differences between populations
95
_____ speciation is much rarer than ____ speciation
sympatric, allopetric
96
what is a phylogenetic tree?
branching diagram showing the evolutionary relatedness of organisms
97
what are phylogenetics?
studies the evolutionary relationship of organisms
98
what is a node?
point at which 2 branches join together - represents the last common ancestor of the 2 groups
99
what is a sister taxa?
joined together by a node - more closely related to each other than to any other group
100
nodes can be rotated without changing _____
evolutionary relationships
101
what is a monophyletic group?
includes a common ancestor and all of it's descendants
102
what is a paraphyletic group?
includes a common ancestor and some, but not all, of it's decsendants
103
what is a polyphyletic group?
does not include the common ancestor
104
groups on a phylogenetic tree in order from biggest to smallest left to right
phylum - class - order - family - genus - species
105
what is character?
anatomical, physiological or molecular features of organisms
106
what is character state?
the observes condition of a character
107
what is the most common feature of an organism?
molecular
108
what does homologous mean?
character is similar in organisms because of a common ancestor
109
what does analogous mean?
character is similar because of similar evolutionary pressures, not because of a common ancestor
110
what are synapamorphies?
shared derived traits, traits that are unique to a particular group and are found in all members of that group
111
phylogenies are ____ about the evolutionary relationships between organisms
hypotheses
112
it is best if named taxa represent ___
monophyletic groups
113
taxonomy may be revised when taxonomic groups are found to be either _____ or ____
paraphyletic, polyphyletic
114
______ are helpful in constructing phylogenies
synapamorphies
115
what is the ingroup?
group under study
116
what is the outgroup?
closely related to, but not a part of the ingroup
117
what is parsimony?
the simplest explanation is best - least evolutionary changes
118
most modern phylogenetic trees are built using _____ from _____, _____, or ______
molecular sequence data, DNA, RNA, proteins
119
what are fossils?
the remains of past organisms
120
what are trace fossils?
preserved evidence of past organisms but not a piece of the organism itself
121
what is an example of a trace fossil?
dino foot prints
122
what are molecular fossils?
preserved molecules of an organism
123
what is an example of a molecular fossil?
DNA and RNA
124
what is a fossil record?
history of an organism
125
what is the bias in the fossil record?
biased to
-organisms that live in the sea
-organisms that are wide spread or numerous
-organisms with hard parts
126
