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Biology 1407-01 > Chapter 13: How Populations Evolve > Flashcards

Chapter 13: How Populations Evolve Flashcards

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1
Q

Aristotle believed…

A

life is fixed

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2
Q

describe Lamarkian Inheritance

A
  • inheritance of acquired characteristics

- lineages don’t go extinct

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3
Q

What helped shape the theory of evolution and natural selection?

A

worldwide voyages

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4
Q

list some observations from travels?

A
  • organisms within geographic proximity are more similar
  • the planet is changing
  • fossils resemble individuals extinct to a region
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5
Q

Darwin called his theory

A

descent with modification

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6
Q

decent with modifications explains

A
  • all life is connected by a common ancestor

- descendants have accumulated adaptations

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7
Q

define a theory…

A

a widely accepted explanatory idea

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8
Q

fossil record provides evidence for

A

evolution

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9
Q

3 characteristics of fossils

A
  • imprints of past organisms
  • document differences between past and present organisms
  • reveals that many species are extinct
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10
Q

in the late 1970s paleontologists thought whales arose from

A

a wolf-like carnivore

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11
Q

define homology

A

similarity due to shared ancestry between a pair of structures or genes

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12
Q

what reveals evolutionary relationships?

A

structural and molecular homologies

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13
Q

DNA also shares

A

evolutionary history

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14
Q

define vestigial structures

A

remnants of features that serve important functions in the organisms ancestor

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15
Q

define evolutionary tree

A

branch diagram showing the evolutionary relationship among organisms

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16
Q

define the nodes of an evolutionary tree

A

represents the common ancestor

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17
Q

define the hatch of an evolutionary tree

A

the shared homologous structure

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18
Q

define a clade of an evolutionary tree.

A

all organisms that share a common ancestor

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19
Q

Darwin proposed what as the mechanism of evolution?

A

natural selection

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20
Q

What was Darwin’s greatest contribution to biology?

A

his explanation of how life evolves

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21
Q

artificial selection shows insights into…

A

how incremental change occurs

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22
Q

Difference between artificial selection and natural selection?

A

artificial selection can bring change in a short period of time

natural selection modifies species over thousands of generations

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23
Q

What is heritable?

A

natural variation in a population

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24
Q

overtime favorable traits…

A

accumulate in a population

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25
Q

list the 3 key points to natural selection

A
  1. the population, not the individual, evolves
  2. natural selection ONLY acts on heritable traits
  3. evolution is not goal directed
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26
Q

evolution is AKA

A

change in allele frequencies

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27
Q

What is an example of natural selection in action?

A
  • the evolution of pesticide resistance in hundreds of insect species
  • human resistance to antibiotics
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28
Q

give 2 examples of how natural selection can be observed in natural populations

A
  1. Galapagos finches and drought

2. black snakes and invasive toads

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29
Q

evolutionary adaptation relies on the…

A

available genetic material

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30
Q

examples of available genetic material include?

A
  • changes in allele frequencies through time

- varying population that fits the current and local environment

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31
Q

What produces the genetic variation that makes evolution possible?

A

mutation and sexual reproduction

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32
Q

Organisms typically show…

A

individual variation

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33
Q

Define mutations…

A

the ultimate source of genetic variation that serves as raw material for evolution

an alteration or change in DNA sequence

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34
Q

In organisms that reproduce sexually, where does most of the genetic variation in that population come from?

A

the unique recombination of alleles inherited by each individual

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35
Q

define a gene

A

a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product

36
Q

define an allele

A

alternate from of a gene

37
Q

many alleles form a gene and many genes form a

A

trait

38
Q

mutation characteristics…

A
  • can provide novel or improved gene function

- most often deleterious and quickly removed from a population

39
Q

what is an example of a mutation?

A

garter snakes become resistant to the poison of frogs, but it cost them the agility of being able to move quickly

40
Q

3 ways that sexual reproduction contributes to genetic variation

A
  1. crossing over
  2. independent assortment of alleles (in metaphase 1)
  3. random fertilization
41
Q

define synapsis

A

pairing up of homologous chromosomes in meiotic prophase

42
Q

What occurs during synapsis?

A
  • each pair of homologous chromosomes form a bivalent

- bivalents condense an form a tetrad

43
Q

chiasma forms during

A

prophase I

44
Q

define crossing over

A

nonsister chromatids exchange genetic material

45
Q

define terminalization

A

centromeres attach to spindles and nuclear envelope breaks down

46
Q

what holds the nonsister chromatids together?

A

terminal chiasmata

47
Q

during anaphase I

A
  • homologous chromosomes separate

- nondisjunction may occur

48
Q

characteristic of telophase I

A

reappearance of nuclear membrane and short interphase

49
Q

when does crossing over occur?

A

during meiotic prophase

50
Q

What results in a great amount of genetic variability?

A

crossing over

51
Q

formula for the number of unique gametes

A

2^(# of paired chromosomes)

52
Q

define a population

A

a group of individuals that live in the same area and interbreed

53
Q

define a gene pool

A

all copies of every type of allele, at every locus, in all members of the population

54
Q

define microevolution

A

a change in frequencies of alleles in a population’s gene pool and evolution occurring at a small scale

55
Q

what are Mendel’s postulates?

A
  • genes exist in pairs
  • dominant/ recessive alleles
  • unit factors segregate independently
  • independent assortment
56
Q

what does the Hardy-Weinberg equilibrium state that alleles and genotype frequencies will remain constant if…

A
  • a population is infinitely large (no genetic drift can occur)
  • mating is random
  • no mutations
  • no gene flow
  • no natural selection
57
Q

What shows if a population is evolving?

A

changes in allele frequencies

58
Q

define gene flow

A

transfer of genetic material from one population to another

new alleles at different frequencies

59
Q

what equation holds true when a population is not evolving?

A

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

60
Q

How do public health scientists use the Hardy-Weinberg equilibrium?

A

to estimate how many ppl are carry alleles for certain inherited diseases

61
Q

mechanisms of microevolution

A
  • genetic drift
  • selection
  • gene flow
62
Q

define genetic drift

A

changes in allele frequencies from chance alone (in small pop.)

63
Q

define selection

A

changes in allele frequency from differential reproduction

64
Q

genetic drift is often caused by

A
  • bottleneck effect

- founders affect

65
Q

define bottleneck effect

A

loss of genetic diversity when a population is greatly reduced

66
Q

define founder’s effect

A

when a few individuals colonize an island or other new habitat

67
Q

the bottleneck effect and founder effect are more pronounced in

A

SMALL populations

68
Q

What is often a major consideration in endangered species?

A

inbreeding depression

69
Q

define inbreeding depression

A

negative effect of homozygosity on a population

70
Q

what is the ONLY evolutionary force that consistently leads to adaptive change in a population?

A

natural selection

71
Q

what increases as a result of natural selection?

A

favorable traits

72
Q

define relative fitness

A

contribution one makes to the gene pool of the next generation, relative to the contributions of other individuals

73
Q

What are the 3 different types of selection?

A
  1. directional
  2. stabilizing
  3. disruptive
74
Q

describe directional selection

A

one spectrum of a phenotype has higher fitness than the other

75
Q

describe stabilizing selection

A

lower fitness of extreme phenotypes

76
Q

describe diversifying selection

A

extreme phenotypes are more extreme than intermediate ones

77
Q

define sexual selection

A

a form of natural selection in which individuals with certain characteristics are more likely to secure a mate

78
Q

what are the 3 types of sexual selection?

A
  1. INTRAsexual selection
  2. INTERsexual selection
  3. honest vs. dishonest signaling
79
Q

define intrasexual selection

A

occurs when individuals compete directly with members of the same sex for mates

80
Q

intersexual selection

A

selection in mate choice

-females being choosy in selecting their mates

81
Q

How do we contribute to the problem of antibiotic resistance?

A
  • doctors overprescribing antibiotics
  • patients prematurely stop taking antibiotics
  • livestock producers add antibiotics to animal feed
82
Q

How does diploidy preserve variation?

A

by “hiding” recessive alleles through balancing selection and heterozygous advantage

83
Q

when does balancing selection occur?

A

when natural selection maintains stable frequencies of two or more phenotypic forms in a population

84
Q

Give an example of balancing selection

A

side blotched lizards

85
Q

define heterozygote advantage

A

heterozygous individuals have a greater reproductive success than either type of homozygote. Results that 2 or more alleles for a gene are maintained in the population

86
Q

examples of heterozygote advantage

A

sickle cell gene and malaria

Biology 1407-01 (14 decks)

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