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BIOL 1105 > 23: Systematics > Flashcards

23: Systematics Flashcards

Module 4, Lesson 6

1
Q

True or false:

The fossil record provides a complete timeline of every species through time.

A

False

The fossil record is imperfect.

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2
Q

If the fossil record were perfect, we would be able to…

A

Easily trace evolutionary relationships

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3
Q

True or false:

The fossil record is the only source of evidence scientists use to form hypotheses about evolutionary relationships.

A

False

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4
Q

The reconstruction and study of evolutionary relationships is called…

A

Systematics

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5
Q

Scientists can present hypotheses about evolutionary relatio ships between species by constructing…

A

Phylogenies

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6
Q

____ are branching tree diagrams that illustrate the evolutionary relationships between species.

A

Phylogenies

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7
Q

____ are a type of phylogenies that do not include any scales for the evolutionary changes they depict.

A

Cladograms

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8
Q

A phylogeny should be interpreted by looking at…

A

How recently species shared a common ancestor

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9
Q

True or false:

The arrangement of species in a phylogeny can be used to interpret it.

A

False

It is possible to arrange the same phylogeny in different ways without altering the evolutionary relationships.

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10
Q

Phylogenies are hypotheses based on…

A

The best available data

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11
Q

Other than the fossil record, list four sources of data that can be used to construct phylogenies.

A
  1. Molecular (DNA and proteins)
  2. Morphology
  3. Physiology
  4. Behavior
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12
Q

The most common source of data for generating phylogenies is…

A

Molecular
(from DNA and proteins)

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13
Q

In order to be meaningful, a phylogeny must be rooted with a(n)…

A

Outgroup

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14
Q

Taxa that are closely related to, but not members of, the group being studied are called…

A

Outgroups

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15
Q

A similarity between species that arose from their most recent common ancestor is called a(n)…

A

Ancestral character

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16
Q

A similarity that arose more recently and thus is only present in a subset of the ingroup is called a(n)…

A

Derived character

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17
Q

In order to make a hypothesis about the derived state of the characters, we must first know…

A

The ancestral state of the characters

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18
Q

The process of determining an ancestral state is called…

A

Polarizing the characters

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19
Q

Characters can be polarized using a(n)…

A

Outgroup

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20
Q

The group of organisms/taxa being studied is called the…

A

Ingroup

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21
Q

A trait possessed by all members of the ingroup but not by the outgroup is called an…

A

Ancestral trait

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22
Q

A group of species that share a common ancestor is called a…

A

Clade

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23
Q

A derived character shared by clade members is called a…

A

Synapomorphy

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24
Q

A point of divergence in an organism’s evolutionary lineage is called a…

A

Node

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25
Q

List three major approaches to phylogenetics.

A
  1. Cladistics
  2. The molecular clock
  3. Statistical approaches
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26
Q

The cladistics approach to phylogenetics relies on the principle of…

A

Parsimony

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27
Q

The principle of parsimony states that…

A

The phylogeny that requires the fewest evolutionary events is considered the best hypothesis of the evolutionary relationship between taxa

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28
Q

____ similarities between species were inherited from their most recent common ancestor.

A

Derived

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29
Q

____ similarities between species arose prior to their most recent common ancestor.

A

Ancestral

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30
Q

Characters are polarized by determining…

A

Which are ancestral and which are derived

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31
Q

Which type(s) of characters are considered informative for constructing the phylogeny?

A

Shared derived characters

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32
Q

True or false:

Shared ancestral characteristics are not used to construct phylogenies.

A

True

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33
Q

Phylogenies based on morphological data are constructed according to…

A

The presence or absence of a character

34
Q

Species with similar derived characters are grouped together as…

A

Sister taxa

35
Q

The member of the ingroup that shares the fewest derived characters with the other members is placed next to the…

36
Q

The member of the ingroup with the fewest shared derived characteristics can be considered sister to the clade containing the…

A

Rest of the ingroup

37
Q

Cladistic analyses may be complicated by…

38
Q

True or false:

The degree of similarity between organisms is a good predictor of their evolutionary relationship.

39
Q

A shared character state that has not been inherited from a common ancestor is referred to as…

40
Q

List two causes of homoplasy.

A
  1. Convergent evolution
  2. Evolutionary reversal
41
Q

____ occurs when similar traits evolve independently (are not inherited from a common ancestor)

A

Convergent evolution

42
Q

____ occurs when a trait has reverted back to an earlier state

A

Evolutionary reversal

43
Q

True or falseL

Molecular analyses using DNA sequence data are generally favored over morphological data.

44
Q

Why are molecular analyses using DNA sequence data a preferred source of data for phylogenies?

A

They provide many more characters to construct the phylogeny with

45
Q

When constructing a phylogeny using DNA sequence data, ____ are used as synapomorphies.

A

Changes in specific nucleotides

46
Q

In order to find the most parsimonious relationship among phylogenies constructed using DNA sequence data, scientists must…

A

Use a computer program

47
Q

True or false:

Most phylogenies also provide information about the timing of evolutionary changes.

48
Q

Models can estimate the timeframe of species divergence events based on…

A

The rate at which DNA mutations occur

49
Q

When are analyses using the “molecular clock” considered most reliable?

A

When the divergence of a group can be calibrated using the fossil record

50
Q

Why can traditional “molecular clock” models sometimes be unreliable?

A

Rates of evolution are not always constant

51
Q

The approximate age of a node can be adjusted using…

A

Knowledge about the age of a relevant fossil

52
Q

____ allow independent assumptions to be made about the rate at which different characters in the analysis evolved.

A

Statistical approaches

53
Q

Statistical approaches to phylogenies are useful in cases where…

A

Evolution has occurred rapidly

54
Q

Statistical approaches to phylogenies begin with assumptions about…

A

The rate of character evolution

55
Q

Statistical approaches are more effective than maximum parsimony at dealing with homoplasy when…

A

Rates of evolutionary change are high

56
Q

The process of placing groups of species into the taxonomic hierarchy is…

A

Classification

57
Q

A ____ includes the most recent common ancestor and all of its descendants.

A

Monophyletic group

58
Q

A ____ includes the most recent common ancestor but not all of its descendants.

A

Paraphyletic group

59
Q

A ____ does not contain the common ancestor for all members of the group.

A

Polyphyletic group

60
Q

True or false:

Systematics and traditional classification tend to be in agreement.

61
Q

Because taxonomic hierarchies are based on shared traits, they should…

A

Reflect evolutionary relationships

62
Q

True or false:

Established taxonomic groups do not always match current understanding of phylogenetic relationships.

63
Q

True or false:

According to recent phylogenetic advances, placing birds and reptiles in separate monophyletic groups does not make sense.

64
Q

Phylogenetics is the basis of…

A

Comparative biology

65
Q

We can learn a lot about why evolution proceeded the way it did by examining…

A

Traits among species in the context of their evolutionary relationships

66
Q

____ are derived from the same body part in a common ancestor.

A

Homologous structures

67
Q

Dolphins’ fins and a horse’s legs are examples of…

A

Homologous structures

68
Q

____ are similar structures derived from different ancestral sources.

A

Homoplastic structures

69
Q

A bird’s wings and a dragonfly’s wings are examples of…

A

Homoplastic structures

70
Q

Phylogenies can illustrate….

A

Convergent evolution

71
Q

____ illustrate how complex characters gradually evolved over millions of years.

A

Phylogenies

72
Q

Phylogenetics helps explain…

A

Species diversification

73
Q

Explaining patterns of species diversity is a central goal of…

A

Evolutionary biology

74
Q

The number of species per clade is referred to as…

A

Species richness

75
Q

____ can be used to propose and test hypotheses about species richness.

A

Phylogenetic analyses

76
Q

Phylogenies can illustrate patterns of…

77
Q

Biogeographical data can be incorporated into a phylogenetic analysis to test hypotheses about…

A

The center of origin and pattern of dispersal for a group of taxa

78
Q

____ can be used to study how diseases jump between species.

A

Phylogenies

79
Q

True or false:

Scientists can use phylogenies to determine the general time and location where a disease first infected humans.

80
Q

Phylogenies can be used to identify the source of infection in diseases that…

A

Mutate rapidly

81
Q

List six areas of study in which phylogenies can be applied.

A
  1. Comparative biology
  2. Convergent evolution
  3. Sequences of evolutionary change
  4. Species diversification
  5. Patterns of dispersal
  6. Disease evolution

BIOL 1105 (26 decks)

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