Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

nop > 25 > Flashcards

25 Flashcards

1
Q

phylogeny

A

(phylon - tribe, genesis - origin)

the evolutionary history of a species or group of species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

systematics

A

an analytical approach to understanding the diversity and relationships of organisms, both present-day and extinct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

systematists have traditionally studied __ and __ among organisms as a basis for inferring evolutionary relationships. in recent decades, systematists have gained a powerful new tool, __

A

morphological, biochemical resemblances;

molecular systematics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

molecular systematics

A

uses comparisons of DNA, RNA, and other molecules to infer evolutionary relationships between individual genes and even btwn entire genomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

fossils can help establish relationships between living organisms b/c

A

they reveal ancestral characteristics that may have been lost over time in certain lineages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

in order to infer phylogenies, we must study the __, __, and __ of living organisms, as well as __

A

morphologies, development, biochemistry, fossils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

formation of sedimentary rocks

A

sand and silt eroded from the land are carried by rivers to seas and swamps, where the minerals settle to the bottom along w/ remains of organisms. over millions of years, deposits pile up and compress the older sediments below into layers called strata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

fossil record

A

is based on the sequence in which fossils have accumulated in such strata

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

fossils inform phylogeny only if ________, clarifying _______

A

we can determine their ages,

the order in which various characteristics appeared and disappeared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

the fossil record is biased

A

in favor of species that existed for a long time, were abundant and widespread, and had hard shells, skeletons, or other parts that facilitated their fossilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

homologies

A

similarities due to shared ancestry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

if the morphological divergence btwn related species is great and their genetic divergence is small, then we can infer that

A

the morphological diversity of the species is controlled by relatively few genetic differences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

analogy

A

similarity due to convergent evolution rather than to shared ancestry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

a potential red herring in constructing a phylogeny is

A

analogy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

convergent evolution occurs when

A

similar environmental pressures and natural selection produce similar (analogous) adaptations in organisms from diff evolutionary lineages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

homoplasy

A

similar (analogous) structure or molecular sequence that has evolved independently in 2 species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

another clue to distinguishing btwn homology and analogy is to consider

A

the complexity of the characters being compared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

_____________, the less likely it is that the structures evolved independently.

A

the more points of resemblance that 2 complex structures have

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

scientists have so far sequenced _____ bases’ worth of nucleic acid data from thousands of species

A

more than 20 billion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

the fact that molecules have diverged btwn species

A

doesnt in itself tell us how long ago their common ancestor lived

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

just as w/ morhpological characters, it’s necessary to distinguish homology from analogy to determine

A

the usefulnes sof molecular similarities for evolutionary studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

the discipline of systematics dates to ___ when ____

A

1748; linnaeus published systema naturae “system of nature”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

systema naturae

A

linnaeu’s taxonomic classification of all plants and animals known at the time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

taxonomy

A

an ordered division of organisms into categories based on a set of characteristics used to assess similarities and differences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

linnaeus’ classification was based simply on ____ rather than on ____

A

resemblances; evolutionary relationships

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

2 useful features of linnaeus’ ystem

A
  1. binomial designations for species

2. hierarchical classification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

binomial

A

2-part format of the scientific name, instituted by linnaeus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

genus

A

1st part of species’ binomial name

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

specific epithet

A

2nd part of species’ binomial name; is unique for each species within the genus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

format of binomial nomenclature

A

first letter of genus is capitalized, entire bionomial is italicized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

hierarchical classification from most general to most specific?

A

kids playing catch on freeways get smashed

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

taxon

A

the named taxonomic unit at any level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

format of writing taxa?

A

taxa broader than the genus level aren’t italicized, although they’re capitalized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

phylogenetic trees

A

branching diagrams used by systematists to depict their hypotheses about evolutionary relationships

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

a phylogenetic tree is often constructed from

A

a series of dichotomies, or 2-way branch points; each branch point represents the divergence of 2 species from a common ancestor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

vintages

A

actual ages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

cladogram

A

diagram that depicts patterns of shared characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

a cladogram by itself ______

A

doesn’t imply evolutionary history

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

if ______, then the cladogram forms the basis of a phylogenetic tree

A

the shared characteristics are due to common ancestry (that is, if theyre homologous)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

clade

A

within the phylogenetic tree – a clade is defined as a group of species that includes an ancestral species and all its descendants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

cladistics

A

the analysis of how species may be grouped into clades

42
Q

monophyletic

A

a valid clade; pertaining to a grouping of species consisting of an ancestral species and all its descendants

43
Q

paraphyletic

A

consists of an ancestral species and some, but not all, of the descendants

44
Q

a paraphyletic grouping results when

A

we lack information about some members of a clade

45
Q

after systematists have separated homologous from analogous similarties, they must sort thru the homologies to distinguish btwn __ and __

A

shared primitive characters and shared derived characters

46
Q

what does “character” refer to

A

any feature that a particular taxon possesses

47
Q

the characters that are relevant to phylogeny are

A

the homologous ones

48
Q

shared primitive charaacter

A

a character that’s shared beyond the taxon we’re trying to define

49
Q

shared derived character

A

an evolutionary novelty unique to a particular clade

50
Q

systematists use ____ to differentiate btwn shared derived and shared primitive ccharacters

A

outgroup comparison

51
Q

outgroup

A

speices/group that’s closely related to the group of species being studied, but clearly not as closely as any study-group members are to each other

52
Q

ingroup

A

the various species that are being studied

53
Q

outgroup comparison is based on the assumption that

A

homologies present in both the outgroup and ingroup must be primitive characters that predate the divergence of both groups from a common ancestor

54
Q

the species making up the ingroup display

A

a mixture of shared primitive and shared derived characters

55
Q

any chronology represented by the branching pattern of a phylogenetic tree is __ rather than __

A

relative; absolute

56
Q

phylogram

A

diagram in which the length of a branch reflects the number of changes that have taken place in a particular DNA sequence in that lineage

57
Q

humans and bacteria had a common ancestor that lived ____ years ago, and it was a ____

A

over 3 billion years ago; single called prokaryote

58
Q

ultrametric tree

A

same branching pattern as in a phylogram, but all the branches that can be traced from the common ancestor to the present are of equal length

59
Q

ultrametric trees don’t contain the info about ___ that can be found in phylograms

A

diff evolutionary rates

60
Q

ultrametric trees can draw on data from ____ to ____

A

the fossil record; place certain branch points in the context of geologic time

61
Q

maximum parsimony

A

principle that states that we should first investigate the simplest explanation that’s consistent w/ the facts

62
Q

the most parsimonious tree is the one that

A

requires the fewest evolutionary events to have occurred in the form of shared derived characters

63
Q

for phylograms based on DNA sequences, the most parimonious tree

A

requires the fewest base chages

64
Q

maximum nlikelihood

A

given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events

65
Q

computer programs that search for trees that are parsimonious and likely are

A
  1. “distance” methods minimize the total of all the percentage differences among all the sequences
  2. more complex “character-state” methods minimize the total number of base changes or search for the most likely pattern of base changes among all the sequecnes
66
Q

any phylogenetic tree represents

A

a hypothesis about how the various organisms in the tree are related to one another

67
Q

applying parsimony in molecular systematics is more reliable for

A

a data set of many long DNA sequences than for a smaller set

68
Q

occassionally misjudging an analogous similarity in morphology as a homologous character is less likely to distort a phylogenetic tree if

A

each clade in the tree is defined by several derived characters

69
Q

molecular systematics

A

comparing nucleic acids or other molecules to infer relatedness

70
Q

the ability of molecular trees to encompass both short and long periods of time is based on the fact that

A

diff genes evolve at diff rates, even in the same evolutionary lineage

71
Q

since the DNA that codes for ribosomal RNA _____, _____

A

changes relatively slowly, comparisons of DNA sequences in these genes are useful for investigating relationships btwn taxa that diverged hundreds of millions of years ago

72
Q

gene dulication is 1 of the most important types of mutation in evolution b/c

A

it increases the number of genes in the genome, providing opportnities for further evolutionary changes

73
Q

orthologous genes

A

refers to homologous genes that are paassed in a straight line from one generation to the next but have ended up in diff genes pools b/c of speciation

74
Q

paralogous genes

A

result from gene duplication, so they’e found in more than one copy in the same genome

75
Q

orthologous genes can only diverge ____, w/ the result that

A

after speciation has taken place;

the genes are found in separate gene pools

76
Q

paralogous genes can diverge ___, b/c ____

A

even while they’re in the same gene pool;

they’re present in more than one copy in the genome

77
Q

remarkable fact about orthologous genes

A

they’re widespread and can extend over huge evolutionary distances

78
Q

remarkable fact about the number of genes

A

the number of genes seems not to have increased thru duplication at the same rate as phenotypic complexity m

79
Q

molecular clock

A

yardstick for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates

80
Q

the assumption underlying the molecular clock is that

A

the number of nucleotide substitutions in orthologous genes is proportional to the time that has elapsed since the species branched from their common ancestor

81
Q

in the case of paralogous genes, the number of substitutions is

A

proportional to the time since the genes became duplicated

82
Q

we can calibrate the molecular clock of a gene that has a reliable avg rate of evolution by

A

graphing the number of nucleotide diffferences against the times of a series of evolutionary branch points that are known from the fossil record

83
Q

the graph line representing the evolution rate of the molecular clock can then be used to estimate

A

the date of evolutionary episodes that can’t be discerned from the fossil record

84
Q

the regularity of genetic change that enables us to use some genes as molecular clocks raises the possibility that

A

many of the changes in these sequecnes result from genetic drift, and the changes are mostly neutral

85
Q

neutral theory

A

theory that much evolutionary change in genes and proteins has no effect on fitness and therefore isn’t influcned by darwinian selection

86
Q

differences in the rate of the molecular clock in diff genes are a function of

A

how important each gene is

87
Q

if the exact sequence of amino acids a gene specifies is essential to survival, ______

rate of change of genes:

A

most mutational changes will be harmful and only a few will be neutral

slow

88
Q

if the exact sequence of amino acids is less critical,

rate of change of genes:

A

fewer of the new mutations will be harmful and more will be neutral.

more quickly

89
Q

in reality, the molecular clock

A

doesnt run as smoothly as neutral theory predicts

90
Q

many irregularities in molecular clocks are likely to be the result of

A

natural selection in which some DNA changes are favored over others

91
Q

an abundant fossil record extends back about

A

550 million years

92
Q

investigators use 2 creteria to identify regions of DNA molecules that can demonstrate the branchin pattern of the tree of life:

A
  1. regions must be able to be sequenced

2. they must’ve evolved so slowly that homologies btwn even distantly related organisms can still be detected

93
Q

b/c rRNA genes are fundamental to the workings of the cell,

A

their molecular clock runs so slowly that they can serve as the basis for a universal tree of life

94
Q

tree of life has 3 domains:

A

bacteria
archaea
eukarya

95
Q

the domain bacteria contains

A

most of the currently known prokarytes

96
Q

archaea consists of

A

a diverse group of prokaryotic organisms that inhabit a wide variety of environments

97
Q

eukarya conssts of

A

all the organisms that have cells containing true nuclei

98
Q

comparisons of complete genomes from the 3 domains show that, esp during the early hsitory of life, there have been

A

substantial interchanges of genes btwn organisms in the diff domains

99
Q

horizontal gene transfer

A

in which genes are transferred from one genome to another thru mechanisms such as transposable elements, and perhaps thru fusions of diff organisms

100
Q

the 1st eukaryote may have arisen thru

A

a fusion btwn an ancestran bacterium and an ancestran archaean

nop (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions