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BIOL 1105 > 23: Systematics > Flashcards

23: Systematics Flashcards

Module 4, Lesson 6 (81 cards)

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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
List three major approaches to phylogenetics.
1. Cladistics 2. The molecular clock 3. Statistical approaches
26
The cladistics approach to phylogenetics relies on the principle of...
Parsimony
27
The principle of parsimony states that...
The phylogeny that requires the fewest evolutionary events is considered the best hypothesis of the evolutionary relationship between taxa
28
____ similarities between species were inherited from their most recent common ancestor.
Derived
29
____ similarities between species arose prior to their most recent common ancestor.
Ancestral
30
Characters are polarized by determining...
Which are ancestral and which are derived
31
Which type(s) of characters are considered informative for constructing the phylogeny?
Shared derived characters
32
# True or false: Shared ancestral characteristics are not used to construct phylogenies.
True
33
Phylogenies based on morphological data are constructed according to...
The presence or absence of a character
34
Species with similar derived characters are grouped together as...
Sister taxa
35
The member of the ingroup that shares the fewest derived characters with the other members is placed next to the...
Outgroup
36
The member of the ingroup with the fewest shared derived characteristics can be considered sister to the clade containing the...
Rest of the ingroup
37
Cladistic analyses may be complicated by...
Homoplasy
38
# True or false: The degree of similarity between organisms is a good predictor of their evolutionary relationship.
False
39
A shared character state that has not been inherited from a common ancestor is referred to as...
Homoplasy
40
List two causes of homoplasy.
1. Convergent evolution 2. Evolutionary reversal
41
____ occurs when similar traits evolve independently (are not inherited from a common ancestor)
Convergent evolution
42
____ occurs when a trait has reverted back to an earlier state
Evolutionary reversal
43
# True or falseL Molecular analyses using DNA sequence data are generally favored over morphological data.
True
44
Why are molecular analyses using DNA sequence data a preferred source of data for phylogenies?
They provide many more characters to construct the phylogeny with
45
When constructing a phylogeny using DNA sequence data, ____ are used as synapomorphies.
Changes in specific nucleotides
46
In order to find the most parsimonious relationship among phylogenies constructed using DNA sequence data, scientists must...
Use a computer program
47
# True or false: Most phylogenies also provide information about the timing of evolutionary changes.
False
48
Models can estimate the timeframe of species divergence events based on...
The rate at which DNA mutations occur
49
When are analyses using the "molecular clock" considered most reliable?
When the divergence of a group can be calibrated using the fossil record
50
Why can traditional "molecular clock" models sometimes be unreliable?
Rates of evolution are not always constant
51
The approximate age of a node can be adjusted using...
Knowledge about the age of a relevant fossil
52
____ allow independent assumptions to be made about the rate at which different characters in the analysis evolved.
Statistical approaches
53
Statistical approaches to phylogenies are useful in cases where...
Evolution has occurred rapidly
54
Statistical approaches to phylogenies begin with assumptions about...
The rate of character evolution
55
Statistical approaches are more effective than maximum parsimony at dealing with homoplasy when...
Rates of evolutionary change are high
56
The process of placing groups of species into the taxonomic hierarchy is...
Classification
57
A ____ includes the most recent common ancestor and all of its descendants.
Monophyletic group
58
A ____ includes the most recent common ancestor but not all of its descendants.
Paraphyletic group
59
A ____ does not contain the common ancestor for all members of the group.
Polyphyletic group
60
# True or false: Systematics and traditional classification tend to be in agreement.
False
61
Because taxonomic hierarchies are based on shared traits, they should...
Reflect evolutionary relationships
62
# True or false: Established taxonomic groups do not always match current understanding of phylogenetic relationships.
True
63
# True or false: According to recent phylogenetic advances, placing birds and reptiles in separate monophyletic groups does not make sense.
True
64
Phylogenetics is the basis of...
Comparative biology
65
We can learn a lot about why evolution proceeded the way it did by examining...
Traits among species in the context of their evolutionary relationships
66
____ are derived from the same body part in a common ancestor.
Homologous structures
67
Dolphins' fins and a horse's legs are examples of...
Homologous structures
68
____ are similar structures derived from different ancestral sources.
Homoplastic structures
69
A bird's wings and a dragonfly's wings are examples of...
Homoplastic structures
70
Phylogenies can illustrate....
Convergent evolution
71
____ illustrate how complex characters gradually evolved over millions of years.
Phylogenies
72
Phylogenetics helps explain...
Species diversification
73
Explaining patterns of species diversity is a central goal of...
Evolutionary biology
74
The number of species per clade is referred to as...
Species richness
75
____ can be used to propose and test hypotheses about species richness.
Phylogenetic analyses
76
Phylogenies can illustrate patterns of...
Dispersal
77
Biogeographical data can be incorporated into a phylogenetic analysis to test hypotheses about...
The center of origin and pattern of dispersal for a group of taxa
78
____ can be used to study how diseases jump between species.
Phylogenies
79
# True or false: Scientists can use phylogenies to determine the general time and location where a disease first infected humans.
True
80
Phylogenies can be used to identify the source of infection in diseases that...
Mutate rapidly
81
List six areas of study in which phylogenies can be applied.
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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