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evolution Flashcards

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Biology 101 flashcards
1
Q

what lead darwin to this observations of common ancestry

A

naturalistic observation; similar special geographically close to each other -> COMMON ANCESTRY

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2
Q

biogeography

A

in different parts of the world you observe different species but the
distribution of species; pattern darwin discovered

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3
Q

homologies

A

structures that have deep, underlying similarities between species; ex. forelimb bone structure

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4
Q

taxonomic group

A

a rank or group of organisms dloped on the basis of their fundamental characteristics, similarities and dissimilarities

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5
Q

transitional fossils

A

a fossil that exhibits characteristics of both ancestral and derived forms

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6
Q

nested structure

A

taxonomies structured as groups within groupse

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7
Q

evidence for common ancestry

A

All life uses the same molecules, DNA and RNA, to store genetic information; always with the
same nitrogenous bases (A, C, G, T, and U

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8
Q

polymorphic population

A

a population with genetic variation; stemming from mutation

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9
Q

Natural selection

A

genetic variants make an organism
better equipped for their environment will increase in frequency in populations over time; survival of the fittest

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10
Q

darwin’s 3 core ideas

A
  • common ancestry
  • if genetic variation is present populations will change
  • natural selection; change in populations over time is adaptive
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11
Q

phylogenetic tree

A

a diagram that shows the evolutionary history of organisms, species, or genes

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12
Q

phylogenetic tree clade

A

a grouping of branches and tips that includes all the descendants of a single ancestral lineage

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13
Q

tree topology

A

representation of relationships between the clades in a tree; gives us
information about relationships

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14
Q

Tree Thinking

A

The ability to use the metaphor of a phylogenetic tree to convey accurate
evolutionary information

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15
Q

Speciation

A

Lineage splitting that ultimately leads to taxa that are classified as separate species

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16
Q

Taxon/ Taxa (plural)

A

a named group of biological organisms, often shown at the tips of a tree

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17
Q

Evidence of Common ancestry (4)

A
  • fossil records
  • biogeography
  • homology
  • classification (hierarchical nesting)
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18
Q

evolution of populations

A

*populations evolve over time
* populations evolve not individuals
*genetic composition of populations change over time

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19
Q

mutation frequency

A

spread of evolution of disease variants; higher frequency = most fit variant

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20
Q

natural selection

A

genetic variants that improve function, reproduction, survival that increase frequency

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21
Q

tree thinking

A

common ancestry depicted in tree form

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22
Q

reasons for split population lineages

A
  • geographic/ climate changes/ rare dispersal events
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23
Q

what do split populations lead to

A

speciation

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24
Q

speciation

A

accumulation of differences -> no longer can interbreed and produce fertile offspring
*form incompatible -> divergence

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25
Q

clade

A

all descendants of ancestral lineage; all meet at 1 node/ common ancestor

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26
Q

sister lineages

A

lineages stemming from the same node

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27
Q

trait evolution

A

genetic changes in a population over time
* happens between nodes

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28
Q

true or false; all species are equally evolved

A

true!

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29
Q

homology

A

similarity of the structure, physiology, or development of different species of organisms based upon their descent from a common evolutionary ancestor

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30
Q

homologous spurs

A

part of tree where all species developed the same trait from the same common ancestor

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31
Q

types of non homology

A

convergence evolution and reversal

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32
Q

convergence evolution

A

nrelated species independently evolve similar traits

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33
Q

reversal

A

reactivation of lost genetic trait from many ancestors ago

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34
Q

parsimony

A

hypothesis that the best way to explain traits on a tree is the way with the fewest changes (least amount of gene develop/ lost)

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35
Q

parsimony assumption

A

loosing and gaining traits equally as likely

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36
Q

placisty of a population

A

genetic changes in population caused by environment; NOT evolution
ex. fertilizers -> plants grown taller

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37
Q

evolution only happens when… (2)

A

1) organisms differ genetically (not environmentally caused)
2) differences in reproductive success; dominant/ better trait more prevalent in next generation.

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38
Q

heritable variation

A

allele variation segregating in a population

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39
Q

segregating variation

A

variation neither lost nor fixed; variable within population

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40
Q

polygenic trait

A

trait controlled by multiple genes

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41
Q

environmental vriation

A

environmental factors that impact genetics; latitude, temp, elevation, developmental environment/ resources available

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42
Q

allele frequency of haploids

A

allele frequency = genotype frequency

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43
Q

allele frequency of diploids

A

A1 (p) = x+ y/2
A2 (q) = z + y/2
*3 possible genotypes

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44
Q

Hardy Weinberg

A

predict genotype frequencies from allele frequencies
- frequency of A1A1= p^2
- frequency of A2A2 = q^2
-frequency of A1A2= 2pq

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45
Q

hardy weinberg assumption

A

random mating

46
Q

directional natural selection

A

when fitness is partially or completely dominant; eventually population’s genotype shift to the fittest trait

47
Q

relative fitness

A

average number of offspring produced by 1 genotype relative to another

48
Q

how is adaptive change supported

A

directional selection

49
Q

trait dominance impact on frequency

A

dominant trait/mutation shows up in population more quickly than incomplete dominance and more than recessive

50
Q

what decreases genetic variation

A

directional selection

51
Q

what replenishes genetic variation

A

random genetic mutations

52
Q

types of mutations

A
  • substitution (silent/ synonymous or synonymous)
    -insertion
    -deletion
53
Q

how is rate of mutation impacted by the “need” of a mutation (environmental problem/ need to adapt to environment)

A

they are independent factors! mutations are random

54
Q

impact of majority of mutations

A

negative/ detrimental

55
Q

genetic drift

A

change in genetic makeup of population by chance fluctuation.

56
Q

what 2 factors lead to genetic drift

A

family size variation and mendelian segregation (only passing 1 allele each to offspring)

57
Q

genetic drift and population size

A

*more dramatic in larger populations
*goes to fixation faster in smaller populations

58
Q

fixation probability

A

higher probability -> goes to fixation faster

59
Q

bottleneck effect

A

large population with lots of variation reduces in size and variation; takes a while to recover and reintroduce variation bc mutations are random and independent of need

60
Q

how does genetic drift impact directional selection

A

small pop: reduces efficacy of directional selection
large pop: directional selection overcomes drift

61
Q

recessive vs dominant diseases mutant alleles

A

higher rate of recessive disease alleles (hides in carriers); dominant disease mutation more lethal -> not passed on through natural selection.

62
Q

overdominant selection

A

heterozygous is more fit than either homozygous; rare alleles most likely to be in heterozygote

63
Q

balanced polymorphism

A

both alleles stay present in the pop because HT is the most favorable (over-domiant selection); occurs at locus with more than 1 allele

64
Q

continuous trait

A

traits controlled by more than 1 gene; complex trait

65
Q

heritability

A

the extent to which variation in a continuous trait has a genetic basis

66
Q

correlation between parent and offspring trait: all variation is genetic

A

slope = 1

67
Q

correlation between parent and offspring trait: all variation is environmental

A

slope = 0

68
Q

strength of selection (s)

A

(mean of reproducing individuals) - (mean of pop)

69
Q

response to selection (r)

A

(mean of offspring gen) - (mean of parent gen)

70
Q

how to find r (response to selection)

A

h^2 * s
(heritability) * (strength of selection)

71
Q

when does the offspring trait distribution differ from the parent trait distribution(shift)

A

when h^2 (heritability) is greater than 0

72
Q

why is heritability hard to measure in/ overesterimated natural population

A

parent and offspring often have same environment -> hard to differentiate between heritability and environmental variation

73
Q

heritability definition

A

percent of variability that is due to genetics
*not individual while population

74
Q

eugenics movement

A

certain traits socially desirable and were assumed to be heritable -> only certain families with “desirable” traits could reproduce.

75
Q

stabilizing selection

A

favors average individuals; reduces trait variation

76
Q

disruptive selection

A

favors extreme individuals; increases trait variation
* to the extreme -> bimodal -> speciation

77
Q

sexual selection

A

reduce/ does not effect individuals ability to survive BUT increases ability to reproduce/ mate

78
Q

secondary sexual characteristics

A

one sex (usually males) develops trait to help reproductive/ mating success
ex. peacock tail feathers

79
Q

sexual dimorphism

A

term used to describe the differences in appearance between the sexes of the same species

80
Q

sexual dimorphism; monogamous vs polygamous species

A

monogamous: little sexual dimorphism
polygamous: more sexual dimorphism

81
Q

why is male sexual dimorphism more extreme?

A

due to higher variance in reproductive output of male offspring

82
Q

what does sexual selection drive the development of

A

male-male conflict and female choosiness

83
Q

runaway sexual selection

A

feedback between female choice and male traits

84
Q

why do trait distributions still have a bell curve shape (average favored) if the average has a lower fitness

A

random mating

85
Q

assorted inbreeding

A

alike individuals more likely to mate with each other
-> leads to bimodal distribution -> speciation

86
Q

Phylogenetic species concept

A

focus on evolutionary history (phylogenetic trees)
- species are taxa
- products of evolution
-sexual and asexual species

87
Q

biological species concept

A

focuses on ability to successfully interbreed and produce fit offspring
- species are populations
-interbreeding throughout time
-only applies to sexual reproduction

88
Q

what geographical model do species subgroups follow?

A

geographically discrete; distinct group 1 and group 2 spanning over geographical distance (small section for intermediate allele frequency)

89
Q

speciation biology

A

evolution of reproductive incompatibility

90
Q

reproductive incompatibility

A

behavioral, genetic, and/or physical differences that reinforce specificity and separation of 2 groups/ species

91
Q

allopatry

A

groups that evolve in different places

92
Q

sympatry

A

groups that evolved in the same place

93
Q

does speciation mostly occur with allopatry or sympatry?

A

allopatry

94
Q

conditions for sympatric speciation

A

strong disruptive selection AND assortative mating

95
Q

complex traits

A

develop by direction selection of multiple little traits over long periods of time; ex. human eye

96
Q

exaptation

A

traits that are beneficial in a species for one function but originated to fulfill a different function ; ex. bird feathers help with flight but originally helped with thermal insolation

97
Q

founders effect

A

occurs when a small group of individuals separates from a larger population, resulting in a reduction in genetic diversity

98
Q

3 origins of life

A

bacteria, archea, eukaryotes

99
Q

evidence for common ancestry(4)

A
  • same proteins/ 20 amino acids
  • same genetic building blocks ; nucleotides
    -same genetic machinery; ribosomes
  • same basic metabolic pathway; make ATP
100
Q

LUCA

A

last universal common ancestor (of archaea, bacteria and eukaryotes)
*complex life forms before LUCA

101
Q

differences between archaea and bacteria

A

bacteria are much more common and interact with the environment and other lifeforms much more

102
Q

cyano bacteria and historical importance

A

bacteria that photosynthesises to produce oxygen; introduced oxygen to earths atmosphere so other life forms could occur

103
Q

Endosymbiotic hypothesis

A

Hypothesis for how mitochondria and plastids formed in eukaryotes: formally prokaryotes with own DNA that were absorbed by and integrated into the eukaryote

104
Q

Autogenous hypothesis

A

competing idea that mitochondria and plastids formed/ have their own DNA because double membrane organelle containing DNA splits into 22; nucleus and mitochondria/ plastid

105
Q

Why exaggerated secondary sexual characteristics are more common in males than females?

A

Because males often differ greatly in mating success, selection more strongly favors traits that improve mating success (even if they lower survival).

106
Q

What is fst

A

FST, or fixation index, is a statistic used to measure the degree of genetic differentiation between populations

107
Q

Does evolution always require natural selection

A

While natural selection is a key mechanism driving evolution, evolution itself does not strictly require natural selection (drift can cause evolution)

108
Q

what must be changing for evolution to be happening

A

allele frequency

109
Q

inside out model; cell development

A

complex eukaryotic cells evolved by pushing out membrane protrusions from their original cell body, creating the internal compartments

110
Q

outside in model; cell development

A

internal structures of a eukaryotic cell formed from plasma membrane folding inwards to create the nucleus and other organelles

bio 152 (7 decks)

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