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Evolutionary Biology > Chapter 2: Tree of Life > Flashcards

Chapter 2: Tree of Life Flashcards

Futuyma, 4th Edition

1
Q

evolutionary change of features within a single lineage (species)

A

anagenesis

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2
Q

branching of a lineage into two or more descendant lineages.

A

cladogenesis

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3
Q

when individuals in one species, or closely related species, acquire enough variations in their traits that it leads to two distinct new species

A

divergent evolution

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4
Q

when two unrelated species develop similar traits because they live in similar environments.

A

convergent evolution

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5
Q

the history of the events by which species or other taxa have successively arisen from common ancestors

A

phylogeny

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6
Q

a diagram that depicts the lines of evolutionary descent of different species, organisms, or genes from a common ancestor.`

A

phylogenetic tree

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7
Q

occur when two lineages merge or form a hybrid descendant so that the tree has a netlike structure.

A

reticulation

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8
Q

the study of relationships among different groups of organisms and their evolutionary development.

A

phylogeny

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9
Q

analysis of DNA and protein structure is used to determine genetic relationships among different organisms.

A

molecular phylogeny

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10
Q

a schematic diagram used as a visual illustration of proposed evolutionary relationships among taxa.

A

phylogenetic tree or cladogram

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11
Q

a classification system that categorizes organisms based on shared traits, or synapomorphies, as determined by genetic, anatomical, and molecular analysis

A

cladistics

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12
Q
  • These are points on a phylogenetic tree where branching occurs.
  • represents the end of the ancestral taxon and the point where a new species splits from its predecessor.
A

nodes

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13
Q
  • These are the lines on a phylogenetic tree that represent ancestral and/or descendant lineages.
  • arising from nodes represent descendant species that split from a common ancestor.
A

branches

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14
Q

This group is a single branch on a phylogenetic tree that represents a group of organisms that are descended from a most recent common ancestor.

A

Monophyletic Group (Clade)

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15
Q

specific groupings or categories of living organisms.

A

taxon (pl. taxa)

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16
Q

Each segment in the tree is a __, or __, which may split at an internal branch point or __, representing the formation of two descendant lineages by __ from their common ancestor.

A
  • lineage, branch
  • node
  • speciation
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17
Q

All the descendants of any one ancestor form a __ (also called a __)

A
  • clade
  • monophyletic group
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18
Q

__ do not indicate time or the amount of difference between groups, whereas __ often indicate time spans between branching points.

A
  • Cladograms
  • phylogenetic trees
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19
Q

illustrates hypothetical relationships between species based on traits

A

cladogram

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20
Q

do not describe the process of evolution, and they don’t reflect the amount of difference between groups

A

cladograms

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21
Q

the branch lengths represent __—these are technically called __

A
  • time
  • phylograms
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22
Q

the term that describes two lineages that come from the same branch point, or node.

A

sister taxa

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23
Q

represents the divergence of two species, and the two species’ most recent common ancestor.

A

branch point

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24
Q

shows the common ancestor of all species in the tree

A

rooted phylogenetic tree

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25
Q

a lineage that does not branch again after it branches from the root

A

basal taxon

26
Q
  • a branch of more than two species.
  • appear when we don’t have enough information to determine branch placement.
A

polytomy

27
Q

The lineage leading to the __ (MRCA) of all the species in the phylogeny is called the __ of the tree.

A
  • most recent common ancestor
  • root
28
Q

Even though certain aspects of similarity may be used as data to determine the relationships among species, a phylogeny portrays relationship (__), not similarity.

A

common ancestry

29
Q

A phylogenetic tree may be drawn in any of several equivalent ways. The junctions may be __ or __.

A

angular or rectangular

30
Q

Our estimate of how taxa are related to one another is based on characteristics that are __ among the taxa

A

homologous

31
Q

the group of taxa that is investigated for determining evolutionary relationships. They are closely related taxa or sister taxa.

A

ingroup

32
Q
  • a reference group that is outside the group of interest.
  • distantly related to the group of taxa investigated.
A

outgroup

33
Q

__ principle is basic to all science and tells us to choose the simplest scientific explanation that fits the evidence. In terms of tree-building, that means that all other things being equal, the best hypothesis is the one that requires the fewest evolutionary changes.

A

parsimony

34
Q

A branching tree that portrays the history of DNA sequences of a gene (__) is often called a __ or a __

A
  • haplotypes
  • gene tree
  • gene genealogy
35
Q

genes that originate from an ancestral gene duplication

A

paralogous

36
Q

genes that diverge from a common ancestral gene by phylogenetic splitting at the organismal level (i.e., homologous in the usual sense).

A

orthologous

37
Q

Two segments of DNA can have shared ancestry because of either a speciation event (__) or a duplication event (__).

A
  • orthologs
  • paralogs
38
Q

Sequence regions that are homologous are also called __

A

conserved

39
Q

are genes in different species that originated by vertical descent from a single gene of the last common ancestor

A

orthologs or orthologous genes

40
Q

As long as the increase is linear with time, the difference in sequence can serve as a __.

A

molecular clock

40
Q

often belong to the same species, but this is not necessary

A

paralogs or paralogous genes

41
Q

the same or similar function, but sometimes do not

A

paralogs or paralogous

42
Q

Patterns of evolution

A
  1. Most features of organisms have been modified from pre-existing features
  2. Rates of character evolution differ
  3. Evolution is often gradual
  4. Homoplasy is common
  5. Phylogenies describe patterns of diversification
43
Q

The most common criteria for hypothesizing homology of anatomical characters are:

A
  1. correspondence of position relative to other parts of the body
  2. correspondence of structure (the parts of which a complex feature is composed).
44
Q

not a useful criterion for homology

A

Correspondence of shape or of function

45
Q

retained with little or no change over long periods among the many descendants of an ancestor.

A

conservative characters

46
Q

Evolution of different characters at different rates within a lineage is called __

A

mosaic evolution

47
Q

Darwin argued that evolution proceeds by small successive changes (__) rather than by large “leaps” (__).

A
  • gradualism
  • saltations
48
Q

the independent evolution of a character or character state in different

A

homoplasy

49
Q

a term that has been used to describe cases in which independent evolution of a character state is thought to have similar genetic and developmental bases, especially in closely related species

A

parallel evolution

50
Q

constitute a return from a derived character state to a more ancestral state.

A

evolutionary reversals

51
Q

It was long assumed that complex characters, once lost, are unlikely to be regained, a principle known as __.

A

Dollo’s law

52
Q

often adaptations by different lineages to similar environmental conditions.

A

convergent features

53
Q

If the time of each branching point in a phylogeny has been estimated by a calibrated __, the phylogeny may suggest whether new lineages arose steadily over a long period, or episodically, in one or more bursts of diversification.

A

molecular clock

54
Q

Divergent evolution of numerous related lineages within a relatively short time is called __

A

evolutionary radiation/ adaptive radiation

55
Q

probably the most common pattern of long-term evolution.

A

directional evolutionary trends

56
Q

Evidence for evolution

A
  1. The hierarchical organization of life.
  2. Homology
  3. Embryological similarities
  4. Vestigial characters
  5. Convergence
  6. Suboptimal design
  7. Geographic distributions
  8. Intermediate forms
57
Q

Darwin listed a dozen vestigial features in the human body

A
  • the appendix
  • the coccyx (four fused tail vertebrae)
  • posterior molars, or wisdom teeth, that fail to erupt, or do so aberrantly, in many people.
58
Q

sequences that retain some similarity to the functional genes from which they have been derived.

A

pseudogenes

59
Q

the origination of a lineage through the partial merging of two ancestor lineages, leading to relationships better described by a phylogenetic network than a bifurcating tree.

A

Reticulate evolution

Evolutionary Biology (15 decks)

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