Ch. 20 - Phylogeny Flashcards

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1
Q

What is phylogeny?

A

The evolutionary history of species alive today

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2
Q

What is systematics?

A

A discipline focused on classifying organisms and determining their evolutionary relationships

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3
Q

what is taxonomy?

A

how organisms are named and classified

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4
Q

what is the arrangement of hierarchical classification?

A

species, genus, family, order, class, phylum, kingdom, domain

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5
Q

what is a taxon?

A

a taxonomic unit at any level of the hierarchy

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6
Q

what is a phylogenic tree?

A

a representation of evolutionary history of a group of organisms

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7
Q

what is a branch point?

A

a representation of the divergence of two evolutionary lineages from a common ancestor

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8
Q

what are sister taxa?

A

groups of organisms that share an immediate common ancestor

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9
Q

what does rooted mean?

A

that a branch point within the tree represents the most recent common ancestor of all taxa in the tree

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10
Q

what is a basal taxon?

A

a linage that diverges early in the history of a group bend

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11
Q

what is polytomy?

A

a branch point from which more than two descendant groups emerge

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12
Q

what are phylogenetic trees based off of?

A

patterns of descent, NOT phenotypic similarities

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13
Q

what is cladistics?

A

systematics in which common ancestry is the primary criterion used to classify organisms

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14
Q

what is a clade?

A

a group of species that includes an ancestral species and all of its descendants

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15
Q

monophyletic

A

consists of an ancestral species and all of its descendants

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16
Q

paraphyletic

A

consists of an ancestral species and some of its descendants

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17
Q

polyphyletic

A

includes taxa with different ancestors

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18
Q

shared ancestral character

A

a characteristic that originated in an ancestor of the taxon

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19
Q

shared derived character

A

an evolutionary novelty unique to a clade

20
Q

outgroup

A

a species or group of species from an evolutionary lineage that is known to have diverged before a lineage (the ungroup)

21
Q

what is the most parsimonious tree?

A

a tree with the fewest evolutionary changes

22
Q

phylogenetic trees are facts, true or false?

A

false, they are hypotheses

23
Q

molecular clock

A

an approach to predict the absolute time of evolutionary changed based on the observation that some genes evolve at constant rates

24
Q

horizontal gene transfer

A

a process in which genes are transferred from one genome to another through mechanisms such as exchange of transposable elements and plasmid, viral infections and perhaps fusion

25
Q

The analytical approach to understanding the diversity and relatedness of both extant and extinct organisms is called…

A

systematics

26
Q

what is the focus of the branch of biology called taxonomy?

A

the classification of life-forms by their similarities and differences

27
Q

The binomial system assigns to each organism a unique name that describes its…

A

genus and species

28
Q

The two-part format of the scientific name, referred to as binomial, ensures that…

A

scientific names avoid ambiguity

29
Q

The correct use of binomial nomenclature requires…

A

both genus and species, both italicized or underlined. Genus is always capitalized and species is always lowercase.

30
Q

A taxon…

A

is a formal grouping at any given level

31
Q

Species A and species B are in the same phylum. Species A and species C, but not species B, are in the same order. From this information you can conclude that…

A

species C could be in the same class as species A and B

32
Q

What does a branch point in a phylogenetic tree represent?

A

A branch point represents a point at which two evolutionary lineages split from a common ancestor.

33
Q

Which of the following methods to establish phylogenetic relationships among organisms has been developed most recently?

A

comparing the component sequences of proteins and nucleic acids

34
Q

The wings of a hummingbird and a bee are..

A

analogous

35
Q

Which of the following would be the least useful in determining the relationships among various species?

A

analogous structures

36
Q

A phylogenetic tree of bird families constructed by cladistic analysis would be a hypothesis about which of the following?

A

evolutionary relationships among bird families

37
Q

Using cladistic analysis, a taxonomist wishes to construct a phylogenetic tree showing the relationships among various species of mammals. Which of the following would be the least useful for this purpose?

A

the fact that all mammals have hair

38
Q

Which statement below is true about an outgroup?

A

The outgroup should be less closely related to any members of the ingroup than they are to each other.

39
Q

Unlike a regular phylogenetic tree, phylogenetic trees with branch lengths proportional to time can be used to…

A

represent the chronological time that has passed since two groups diverged from a common ancestor

40
Q

Which statement below is true of parsimonious trees?

A

Your Answer:

The best tree requires the fewest evolutionary events to have occurred in the form of shared derived characters.

41
Q

Birds and mammals have a four-chambered heart, but most reptiles have a three-chambered heart. How does this fact affect the construction of phylogenetic trees for these groups?

A

The most likely tree is not always the most parsimonious.

42
Q

Which of the following best summarizes the neutral theory?

A

Darwinian selection does not influence a lot of evolutionary change in genes and proteins because many of these changes do not affect fitness. most mutations do not have a large effect on an organism’s fitness.

43
Q

The idea of using molecules as clocks to time evolutionary events is very attractive, but there are many problems in actually applying the technique. What seems to be the best way to get reliable results?

A

It is important to use as many genes as possible. With this approach, fluctuations in evolutionary rate will tend to average out.

44
Q

To which domain is the domain Eukarya (the domain to which humans belong) most closely related?

A

it is not clear whether eukaryotes are more closely related to bacteria or archaea.

45
Q

Universal phylogenetic trees built from different genes sometimes give inconsistent results. What basic assumption on which phylogenetic trees are based has probably been violated during the history of life?

A

Genes are passed vertically from one generation to the next.