Before midterm 1 Flashcards
(105 cards)
1
Q
what is biological evolution?
A
any change in the inherited traits of a population that occur from 1 generation to the next
2
Q
what are the 2 main concepts of evolution?
A
natural selection and descent with modification
3
Q
what species have larger males than females?
A
mammals
4
Q
why might females be larger than males?
A
egg production
5
Q
will traits that are not inherited be passed to the next generation?
A
no
6
Q
what are the main points of special creation?
A
- each organism originated independently
- all have remained the same since creation
- all created recently
7
Q
what is methodological naturalism?
A
science that rejects supernatural explanations.
8
Q
what did Nicolaus Steno study/discover?
A
- fossils
- rocks have layers
- Earth has history
9
Q
what is stratigraphy?
A
the study of strata
10
Q
what did carolus Linnaeus establish?
A
taxonomy
11
Q
did carolus Linnaeus think species were changing or unchanging?
A
unchanging
12
Q
What was George Buffon the first to hint at?
A
evolution - species changing
13
Q
what was Jean-Baptiste Lamarck the first to have?
A
a detailed theory of evolution
14
Q
what did Jean-Baptiste Lamarck’s theory of evolution involve?
A
simplest forms of life continue to arise from inanimate matter that evolve to create higher life forms
- species change through time by inheritance of acquired characters
15
Q
what is uniformitarianism?
A
observable present natural processes responsible for events in the past
16
Q
what did Darwin observe?
A
- lots of diversity in similar forms
- species seem to fit the environments
- fossils are recognizably associated with extant fauna but yet were dramatically different
- similarities due to common ancestors
17
Q
what is the law of succession?
A
fossils and living organisms from one area were similar to each other but different from those in different areas.
18
Q
what is fitness regarding evolution?
A
a measure of the appropriateness of an individual’s attributes for a particular environment
19
Q
how quickly does natural selection work?
A
slowly over a long period of time
20
Q
in comparison to natural selection, how quickly does artificial selection work?
A
drastic changing in a short time period
21
Q
what is modern evolutionary synthesis?
A
emphasis on the interaction between random mutation, natural selection, genetic drift, and gene flow in explaining patterns we see in nature
22
Q
why do we want to infer past evolutionary events?
A
- evolutionary relationships among taxa
- order in which traits emerged
- origin of pathogens and other applications
23
Q
what is phylogeny?
A
a visual representation of the evolutionary history of species or higher taxa
24
Q
what are genealogical tree groups called?
A
families
25
what are phylogenetic tree groups called?
clades
26
what are terminal nodes?
terminal ends of a tree representing species
27
what are internal nodes?
nodes within a phylogeny represent ancestral species
28
what are branches?
lineages evolving independently through time between speciation events
29
what is a cladogram?
phylogeny where time scale is not depicted
30
what are homologous characters?
present in 2 or more taxa because they are inherited from a common ancestor
31
what are analogous characters?
similar in structure or function but have different origins
32
what does it mean when a trait is absent?
ancestral character state
33
what does it mean when a trait is present?
derived character state
34
what does synapomorphy mean?
shared derived character trait
35
what is an outgroup used for?
to infer which character states are ancestral and which are derived
36
what is an outgroup?
a group that is clearly outside the groups who's evolutionary relationships that want to be inferred, but closely related to that group
37
what are outgroups also know as?
basal lineage
38
what is apomorpy?
derived state
39
what is the principle of parsimony?
the hypotheses with the least number of changes to be made is the one that is most likely to have occurred
40
what is homology?
character state similarity due to common descent
41
what is homoplasy?
character state similarity not due to common descent
42
what dates back further; fossils or molecular clock?
molecular clock
43
what is monophyletic?
a group that includes a common ancestor and all of its descendants
44
what is paraphyletic?
contains most recent ancestor but not all the descendants
45
what will happen is a mutation if advantages?
the new allele frequency will increase dramatically in a jumping fashion
46
what happens in a deleterious mutation?
the new allele will reach equilibrium where the mutation rate equals the elimination rate by selection
47
what are the 2 consequences of genetic drift?
random fixation of alleles
| loss of heterozygotes
48
what are the 3 important parameters of genetic drift?
number of individuals
initial allele frequency
number of generations
49
what is the law of large numbers?
the larger the population, the closer the estimate will be to theatre value
50
what happens if selection is strongly against the recessive allele?
the allele will be reduced but not eliminated, if selection is the only force
51
what happens is selection is strongly against the dominant allele?
the allele will be eliminated quickly
52
what is gene flow?
change in allele frequencies due to movement of individuals among populations
53
what is population subdivision?
a balance between genetic drift and gene flow
54
How did the early Greeks try to explain nature?
through the basis of scientific thought
55
Hw did George Buffon believe that creatures were made?
made up of particles that first came together at the start of life
- these made an internal mould that determined the nature of a species
- these particles could change
56
What was Darwin's conclusion of how species were created?
Not created specially but instead evolved trough descent with modification
57
Are physical similarities and evolutionary relatedness linked?
Not necessarily
58
What is convergent evolution?
independent evolution of a similar trait
59
What is evolutionary reversal?
0 to 1 to 0
60
what is population genetics?
Study of the distribution of alleles in populations and causes of allele frequency change
61
what is a gene?
a sequence of DNA transcribed into RNA
62
what is a locus?
a region of DNA. Can include genes, but also non-transcribed regions
63
what is an allele?
a sequence variant at a genetic locus. Mutually exclusive alternative states for a locus.
64
what is a genotype?
Usually the full set of alleles at a locus or set of loci of interest
65
what is a population?
groups of interacting and potentially inbreeding individuals
66
what can Changes in the frequency of traits in a population be traced back to?
changes in the frequency of alleles
67
how do we measure allele frequencies?
Frequency of something=Number of something/Total number of somethings
68
do the basic processes of gamete formation, fertilization, growth and maturation change allele frequencies across generations?
No
69
what does the hardy-weinberg equation assume?
- The population is infinitely large (no genetic drift)
- Genotypes do not differ in fitness (no natural selection)
- There is no mutation
- Mating is random (no inbreeding)
- There is no migration (no gene flow)
70
what is the HW theorem?
Expected relationship between allele and genotype frequencies –don’t change over time IF assumptions met
71
what is w?
relative fitness
72
what happens if a mutation is deleterious?
the new allele will reach equilibrium, where the mutation rate equals the elimination rate by selection
73
is mutation alone a weak or strong evolutionary force?
weak
74
when does selection occur?
when genotypes differ in relative fitness
75
what does rate of change of allele frequencies depend on?
both the fitness of an allele and its frequency
76
what is genetic drift?
Differential reproductive success between individuals, but due to chance rather than to some beneficial aspect of the phenotype
77
what does genetic drift lead to?
changes in allele frequencies across generations
78
what does genetic drift not lead to?
an increase in mean fitness (adaptation)
79
what size population is drift strongest in?
small population
80
what does probability of an allele being fixed depend on?
frequency
81
what are 2 consequences of genetic drift?
1. Random fixation of alleles
| 2. Loss of heterozygosity
82
what are 3 important parameters regarding genetic drift?
1. Number of individuals (Ne)
2. Initial allele frequencies (probability of fixation)
3. Number of generations (time to fixation
83
what size population is natural selection most effective in?
large populations
84
what is a genetic bottleneck?
an event in which the number of individuals in a population is reduced drastically
85
what is the founders effect?
a form of genetic drift
- describes the loss of allelic variation that accompanies the founding of a new population from a very small number if individuals
86
what happens If selection strongly against the recessive allele?
the allele will be reduced but not eliminated, if selection is the only force
87
what happens When the recessive allele is common?
rapid evolution
88
what happens when the recessive allele is rare?
very slow evolution
89
what happens if selection is strongly against the dominant allele?
allele will be eliminated quickly
90
what does the fitness of a phenotype depend on?
on its frequency in the population
91
do dominant beneficial alleles ever go into fixation via selection alone?
no
92
what size population is natural selection most effective in?
larger ones
93
describe over dominance in a stable equilibrium
the allele that selection against will be maintained in the population
Balance: disadvantage of the homozygote = advantage of the heterozygote
94
what is frequency dependent selection?
Fitness of a phenotype depends on its frequency in the population
95
what are potential mechanisms (hypotheses) that may maintain a deleterious allele in a population?
1. mutation-selection balance
2. Heterozygosity superiority
3. Frequency dependant selection
96
what does the selection coefficient (s) equal?
s= 1-w where w is the relative fitness
97
what is gene flow?
change in allele frequencies due to movement of individuals among populations
98
when does Fst=0?
when there is no subdivision of a population.
| will have low drift too
99
when does Fst = 1?
when there is separate populations with no gene flow and high drift.
100
what is inbreeding?
a type of nonrandom mating
101
what is the inbreeding coefficient (F)?
the probability that the two alleles at any locus will be identical by descent
102
does inbreeding increase or decrease the frequency of homozygotes?
increase
103
does inbreeding change allele frequencies?
no, but changes the distribution of alleles among genotypes
104
what is linkage disequilibrium?
Two loci are in linkage disequilibrium when there is a nonrandom association between a chromosome's genotype at one locus and its genotype at the other locu
105
when is a population in linkage equilibrium?
1. The frequency of B on chromosomes carrying A is equal to the frequency of B on chromosomes carrying a, or
2. The frequency of any chromosome type can be calculated by multiplying the frequencies of the constituent allele
