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Science > Natural Selection & Speciation > Flashcards

Natural Selection & Speciation Flashcards

Week 32 Quiz

1
Q

5 factors that signify evolution within a population

A
  1. Genetic mutation
  2. Gene flow (immigration)
  3. Non-random mating
  4. Genetic drift (separation of population)
  5. Selection (predator vs. prey)
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2
Q

Define ‘population’

A

organisms that interbreed to create fertile offspring

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3
Q

Define ‘gene pool’

A

A collection of alleles in a population

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4
Q

Define ‘allele frequency’

A

Commonality of allele; how often it appears

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5
Q

Define ‘evolution’

A

Major changes in alleles; changes in a population over time

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6
Q

What must be true in order for a population to not be evolving?

A
  1. The population is large
  2. there is no migration/gene flow
  3. random mating (no sexual selection)
  4. no natural selection
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7
Q

What does the Hardy-Weinberg Theorem have to do with?

A

Determining allele frequency

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8
Q

Frequency of homo dominant allele equation

A

p x p = p^2

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9
Q

Frequency of homo recessive allele equation

A

q x q = q^2

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10
Q

Frequency of hetero allele equation

A

pq + qp = 2pq

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11
Q

100% of a population (equation of dominant/recessive traits)

A

1 = p^2 + 2pq + q^2

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12
Q

Equation that will not be on the test ( = 100% of gene pool)

A

p + q = 1

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13
Q

Transcription factors are

A

regulatory genes

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14
Q

Activators in gene expression…

A

bind to DNA to increase operon (regulatory & structural gene) transcription

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15
Q

When does most gene regulation occur in Eukaryotes?

A

Transcription during or after RNA/protein production (translation)

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16
Q

Gene Regulation Method 1: Turning on/off access to DNA

A

limits chromatin accessibility; relaxed chromatin allows for transcription better than not

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17
Q

Gene Regulation Method 2: Switching on/off transcription factors

A

Activators or repressors turn on/off genes; turn on/off responses to outside information

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18
Q

Define ‘gene expression’

A

DNA is converted into a functional structure (protein); how cells respond to environment; decides protein production/volume; structure and function

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19
Q

Components of gene expression

A

Promoter, operator, regulatory genes, transcription factors, repressors

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20
Q

Promoter

A

Where RNA polymerase binds on DNA to initiate transcription

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21
Q

Operator

A

DNA segment controlling RNA access to promoter (controlled transcription)

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22
Q

Operon

A

Promoter + operator + structural genes

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23
Q

Inhibitor/repressor protein

A

attaches to operator to inhibit transcription (RNA reaching structural genes)

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24
Q

In order for proteins (genes to be expressed) to be made in response to environmental signals…

A

… RNA polymerase must reach the structural genes

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25
Q

Define ‘genome’

A

Complete genetic material

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26
Q

Advantage of gene expression

A

conservation of resources

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27
Q

Why is gene expression different in eukaryotes than prokaryotes

A

Eukaryotes have bigger genomes, multiple chromosomes, specialized cells, and less operons

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28
Q

Site of transcription in Eukaryotes

A

euchromatin

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29
Q

Does all of a chromatin strand uncoil?

A

No, some are fixed and tightly coiled so they can’t be translated

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30
Q

What segments lie beyond the promoter in Eukarotic genes?

A

Introns (transcribed and not translated (made into a protein))
Exons (transcribed and translated)

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31
Q

On in Eukaryotes, after transcription (that makes pre-mRNA), introns are _____ and exons _____

A

removes, splice (join) one another to make mRNA

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32
Q

Intron removal from pre-mRNA can be catalyzed by

A

ribozymes

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33
Q

Transciption factors may still directly control transciption as it occurs by…

A

placing RNA polymerase on the promoter, or by binding to enhancers that may loop around and touch RNA polymerase and the promoter.

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34
Q

Define ‘cell differentiation’

A

cells develp with specialized functions; the growth of tissues to produce a characteristical form is called morphogenesis.

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35
Q

Homeotic Genes

A

position anatomical structures during morphogenesis; translate into regulator proteins that control patters of developmental genes and adjust rates of cell division.

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36
Q

Homeobox Sequence

A

Homeoboxes (DNA sequence inside homeotic genes) code for protein regulators. Mutations cause developmental abnormalities. Organisms have similar homeoboxes throughout their body.

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37
Q

What do DNA chips do?

A

Track gene expression by noting complementary linking of mRNA and DNA.

38
Q

Cell division regulation proteins are coded by

A

proto-oncogens

39
Q

Oncogens (mutated proto-oncogens) lead to

A

over/untimely expressed cell divison proteins

40
Q

Mutations in tumor supressor genes ______ lead to cancer

A

Directly
(in comparision to mutations in proto-oncogens, which lead to oncogens, which then lead to cancer)

41
Q

Cancer capabilities

A

indefinite divison, neighbor cells unecessary, crowding isn’t a stunt, metastasis

42
Q

Cancer-causing substance

A

carcinogen/mutagen

43
Q

Cancer development risk

A

Genetic susceptibility and carcinogen exposure

44
Q

Kinds of cancer

A

Carcinomans (skin/tissues)
Sarcomas (bone/muscle)
Lymphomas (solid; grow in lymphatic tissues)

45
Q

Biological fitness

A

ability to survive and pass on genes; more offspring = more fitness

46
Q

Natural obstacles

A

food, water, mating competition; pathogens, disease; predators

47
Q

Natural Selection

A

organisms with favorable traits reproduce more; drives evolution; adapts to constant environment; caused by random mutations (positive, negative, neutral)

48
Q

3 types of natural selection

A

Directional, stabilizing, diversifying

49
Q

Directional selection

A

one extreme is favored

50
Q

Stabilizing selection

A

intermediates are favored (mix between two extremes)

51
Q

Diversifying selection

A

two extremes are favored (intermediates not favored)

52
Q

Microevolution

A

a change in allele frequency that is passed on through mutations in sexual reproduction

53
Q

Variation occurs by ________ characteristics and __________ characteristics

A

discrete (one trait or another; extreme), quantative (logged on a continuum)

54
Q

Define ‘polymorphism’

A

Two different traits have equal fitness in a population.

55
Q

average of heterozygous loci

A

Average heterozygosity

56
Q

How to find nucleotide variability

A

compare DNA of two organisms

57
Q

Geographic variation

A

difference between gene pools

58
Q

cline graph

A

shows changing traits along an axis of locations

59
Q

What kinds of cells’ mutations are inherited?

A

Gamete-producing cells’ mutations (germ-line/somatic)

60
Q

Point mutations only affect

A

one base in a gene

61
Q

Mutations in protein production are often harmful

A

change fitness of organism

62
Q

Mutations in non-coding DNA are…

A

harmless

63
Q

Harmful mutations

A

delete, disrupt, rearrange loci, diplicate chromosome large parts

64
Q

Animals and plants have a ______ mutation rate

A

low (1 in 100k genes)
viruses mutate more

65
Q

Define ‘population’

A

interbreeding, offspring producing

66
Q

Define ‘gene pool’

A

all alleles of all loci of a population

67
Q

Mendenlian inheritance laws insure genetic variability

A

not to be confused with Hardy-Weinberg principle of non-evolving populations

68
Q

Genetic Drift

A

unpredictable fluctuation in allele frequencies
Reduces genetic variation thorugh losing alleles
Small gene pools allow for greater deviation
Can make alleles permanent

69
Q

The Founder Effect

A

separated individuals can have different allele frequencies

70
Q

The Bottleneck Effect

A

Environment causes sudden population reduction and changes the gene pool
The smaller population is then subect to gentic drift

71
Q

Gene flow

A

movement of alleles between gene pools through fertile individuals; decreases variation; greater effect on fitness than mutations

72
Q

Relative fitness

A

One’s contibution to gene pool compared to others; selection affects phenotypes to favor genotypes (and thus change genotypes)

73
Q

Why natural selection can’t make perfect organisms

A

It onyl works on previously existing organisms
Evolution has limits
Adaptations are compromises
Natural selection works with environments, which change

74
Q

Adaptive evolution

A

increases survival rate and fitness

75
Q

Sexual selection

A

created sexual dimorphism
intrasexual selection: competition for other sex
intersexual selection: one is choosy about other

76
Q

Diplody

A

tool in preservation of genetic variation that hides recessive alleles

77
Q

balancing selection

A

typical amount of phenotypes present

78
Q

heterozygotes have an advantage because…

A

natural selection allows multiple alleles (multuple positive and/or negative attributes)

79
Q

Frequency-dependent selection

A

fitness declines as phenotype increases in commonality

80
Q

Speciation

A

evolution creates distinct speciesa

81
Q

allopatric speciation

A

new species from geographic isolation

82
Q

Sympatric speciation

A

new species from single ancestor

83
Q

Parapatric speciation

A

new species from partial isolation as new niche enters

84
Q

divergent evolution

A

new species from common ancestor

85
Q

convergent evoltion

A

similar species from different ancestry in similar environemt

86
Q

parallel evolution

A

distinct species with similar traits from a common ancestor

87
Q

coevolution

A

effect of two associated species on each’s evolution

88
Q

analogous structure

A

structurally and derivatively different but have same function

89
Q

homologous structure

A

same basic structure but has different functions

90
Q

Prezygotic isolation

A

reproductive barrier stops zygote (geographic isolation or behavioral isolation)

91
Q

Postzygotic isolation

A

reproduction battier of zygote

92
Q

Cladograms

A

use phylogeny to graph organisms; based on shared derived characteristics
Oldest is at the bottom and descendents branch off.
‘V’ event is where speciation happens.
Clades result from common ancestor groups.

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