Lecture 2 - Taxonomy & Systematics (Part 2) Flashcards

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1
Q

What is Systematic?

A

The theory and a little practice of classifying organisms.

The “Why”

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2
Q

What are people called when they engage in Systematics?

A

Systematists

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3
Q

What do modern Systematists focus on?

A

They focus on the reason why particular taxa should be group together.

ie. The evolutionary reason why things should be grouped together.

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4
Q

What major change happened to systematics in 1960?

A

The focus was switched from simply adding new taxa to methods for determining relatedness among taxa.

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5
Q

Why did the old taxonomies need to be changed in the 1960’s?

A

They were changed out of the desire for evolutionary informative classifications

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6
Q

What was one of the major results of the taxonomies change in the 1960s?

A

Taxonomies in textbooks rapidly became out of date.

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7
Q

What is molecular systematics?

A

it is the use of molecular genetics to study the evolution of relationships among individuals and species

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8
Q

What has the rise of molecular systematics done to taxonomies?

A

It has accelerated the rate of change, due to the use of proteins. DNA, and RNA to better study the relationships of species.

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9
Q

What is the 5 kingdom classification?

A
Bacteria
Protista 
Plantae 
Fungi 
Animalia
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10
Q

What is the modern “kingdom” classification?

A

It involves 10 kingdoms with a new taxonomic level, the domain.

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11
Q

What was systematics like before the 1960’s?

A

it was a Relatively unstructured discipline, although systematists wanted to create a evolutionary sensible classification

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12
Q

What is stratigraphy?

A

The temporal order in which fossils occur

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13
Q

What tools did systematists have before the 1960’s to classify species?

A
  • Stratigraphy
  • Expertise
  • Primitive and advanced morphology
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14
Q

What is Primitive morphology?

A

Morphology based more off of guesses

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15
Q

What is advanced morphology?

A

Morphology based on facts, compared to other facts.

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16
Q

What was one of the major flaws with “old-style” systematics?

A

The methods were subjective, choosing witch classification was the best could be strongly influenced by personal preference.

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17
Q

What invention in the 1960’s allowed for a more objective classification of species within systematics

A

The computer.

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18
Q

Who invented Hennigs systematics? When?

A

German Entomologist Willi Hennig in the 1950’s

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19
Q

What drove the creation of the creation of the Hennigan systematics system?

A

The want for classifications that reflected ancestor-descendant relationships (or more generally shared evolutionary history)

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20
Q

When creating Hennigan systematics, what goal did Willi have in mind?

A

To create a method that was as objective, and transparent as possible.

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21
Q

What did Hennigan systematics argue the best way to determine evolutionary relationships was?

A

Focus on only the shared, derived characteristics.

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22
Q

What is a group of organisms that is related by shared and derived characteristics called?

A

A Calde

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23
Q

What was Hennig’s approach to determining evolutionary relationships called?

A

Cladistics or phylogentic systematics

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24
Q

What does Clados mean?

A

Branch

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25
Q

What does Phylon mean?

A

Tribe, or race

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26
Q

What does gen mean?

A

Create

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27
Q

What is a cladogram?

A

A branching diagaram that shows the hypothesized relationships between species.

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28
Q

What does gramm mean?

A

A mark or a line

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29
Q

What do Cladograms represent?

A

Only the order of evolutionary events (branching) and what taxa share most recent common ancestors.

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30
Q

What do the lengths of the branches on a cladogram mean?

A

Nothing at all

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31
Q

What is the root of a Cladeogram?

A

It is the base node, it represents the hypothetical common ancestror of all the Taxa on that tree.

32
Q

What is a a branching point?

A

It is a part of the cladeogram where a branch diverge from its lineage.

33
Q

What is a dichotomy?

A

A fully resolved split into two taxa.

34
Q

What is a polytomy?

A

A node that is unresolved pattern of divergence.

Looks like a pitchfork

35
Q

What are sister Taxa?`

A

two taxa on the same node.

36
Q

What do the nodes further up the tree represent? (not the root)

A

They represent the more recent, and specific common ancestor.

37
Q

What is a basal taxon?

A

A taxon that is directly attached to the root og the tree and has no further nodes.

38
Q

TO construct a phylogentic hypothesis what information must systematists collect?

A
  • Morphology
  • Behavior
  • DNA sequence
  • Biochemistry
39
Q

What is an Ingroup?

A

A group’s relationships a systematists is interested in untangling

40
Q

What is a character?

A

Each type of structure, behavior, ect of a species.

41
Q

What is a state?

A

The manifestation of a character in a given taxon

42
Q

What is a out group?

A

a more distantly related group of organisms that serves as a reference group when determining the evolutionary relationships of the ingroup.

43
Q

What does Sp. stand for?

A

Species singular

44
Q

What does Spp. stand for?

A

Species Plural

45
Q

Should Sp and Spp be italicized?

A

No

46
Q

What is phyologeny?

A

refers to the evolutionary history of a taxonomic group of organisms

47
Q

What is parsimony?

A

a set of nested relationships that minimizes the number of times a character has to change state.

48
Q

What is Occam’s Razor/ Principle of Parsimony?

A

The best Hypothesis is one that requires the fewest postulations.

ie. the simplest answer is generally the correct answer.

49
Q

What is a matrix?

A

Any grid with X and Y Rows.

50
Q

When a outgroup state is set at “0” on a matrix what is the state concitered to be?

A

Ancestral/original

51
Q

When a outgroup is set at “1” what is the state considered to be?

A

it is derived

52
Q

What does “derived’ mean for an outgroup state?

A

It is a termed character-state polarization because the direction of change in the character is decided.

53
Q

after you create a matrix what are you looking for? What is the goal?

A

Determine a set of nested relationships that minimizes the number of tines 0 changes to 1 / or 1 cnages to 0

54
Q

Changes and relationships among taxa are often presented in what kind of diagram?

A

A Cladogram

55
Q

What is a symplesiomorphy?

A

(cladistics) an ancestral trait shared by two or more taxa of a shared ancestry

56
Q

What does plesio mean?

A

Near/similar to the ancestral state

57
Q

What is a synapomorphiy?

A

(cladistics) a derived trait that is shared by two or more taxa of shared ancestry

58
Q

What is a automorphy?

A

A unique derived character state present in only one taxon.

59
Q

Is the presence of hair a synapomorpy of mammals amoung other vertebrates? what about within mammals?

A

It is a synapomorphy of mammals among other vertabrets

but it is symplesiomorphy within mammals.

60
Q

relationships among taxa are interpereted from what?

A

from the order in which branches split, nit from how many names of taxa are arranged at the tips of branches.

61
Q

true/false:

Trees cannot rotates at its nodes ( like a mobile) without altering the relationships.

A

False

Trees can rotates at its nodes ( like a mobile) without altering the relationships.

62
Q

Cladistics works the best when all character states have the same what?

A

evolutionary origin, called homologous.

63
Q

What does the root word “homo” mean?

A

same.

64
Q

What is it called when character state appears the same but actually evolved independently

A

Analogus, homoplasious, or convergent.

65
Q

molecular phylogenetics in today’s world focus mainly on what?

A

Matching base pairs in selected gene sequences.

66
Q

The more matches there are in the DNA sequence the……

A

The more closely related they are likely to be.

67
Q

What is a set of information that can be displayed through tree length in phylograms.

A

the number of differences between taxa.

68
Q

Constant rate of mutation accumulated allows for what type of construction of trees?

A

Trees with branch lengths that may reflect time since divergence.

69
Q

What is maximum Parsimony?

A

The tree that requires the fewest number of base pair changes

70
Q

Within Molecular Taxonomy what is “maximum Likelihood”?

A

How DNA is most likely to change.

71
Q

What does Monophyletic mean?

A

A true clade; one containing a common ancestor and all of its descendants and no other unrelated TAXA

72
Q

What is the final goal for phylogenic classifications?

A

To reflect ancestor-descendant relationships by creating only momophyletic taxa.

73
Q

What is it called when tAxa do not share recent ancestors and are limped together?

A

polyphyletic

74
Q

What is a Paraphyletic group?

A

Groups that are formed that o not contain all descendants of a common ancestor

75
Q

Hoe are Paraphylectic groups formed?

A

often form the the removal of taxa that are highly divergent fro the rest of the calde