Phylogeny Flashcards

1
Q

application of phylogenetics

A

reconstruct evol history of organisms
understand evol of genes and proteins
framework to understand evol of traits
reconstruct evol of languages

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

Was Darwin aware of Linnaeus’ classification

A

yes

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

define phylogenetic tree

A

mathematical structure used to depict evol history of a group of organisms or genes
show historical relationship, not similarity

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

define systematics

A

infers phylogenetic relationships of organisms and creating classifications based on their evol histories

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

define bifurcation

A

resolved node- 1 ancestor gives rise to 2 descendents

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

define polytomy

A

unresolved node, hard to decipher relatinship

1 ancestral branch giving rise to at least 3 taxa

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

define resolution

A

when 1 ancestral lineage gives rise to 2 descendents

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

t/F: can twist any branch and rearrange order of taxa

A

T

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

define homology

A

ptypic and genetic similarities due to shared ancestry

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

significance of cladograms

A

no meaning, just shows relationship

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

signif of chronograms

A

show time

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

signif of phylograms

A

show amount of change; genetic muts or bp changes

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

T/F: the width of the horizonal axis is signif

A

F

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

define rooted trees

A

implies dirction from last common ancestor to present

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

define unrooted tree

A

don’t know where root is or direction of evol

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

define homologous characters

A

present in a group of species due to shared ancestry

2 kinds

17
Q

what are the 2 types of homologous characters

A

shared derived

shared ancestral

18
Q

define analogous/homoplastic characters

A

present in certain species that have evolved through convergent evol

19
Q

define monophyletic

A

an ancestral species and all its descendants

20
Q

define paraphyletic

A

an ancestral species and some but not all of its descendents

21
Q

define polyphyletic

A

a group without a common ancestor

22
Q

what are 2 important assumptions about phylogen characters

A

they are homologous and are evolving independently from each other

23
Q

most phylogen analyses use…

A

moleculr data

24
Q

why do most phylogen analyses use molecular data

A
genetic basis of characters known
larger amount of phylogen info
any groups of organisms can be compared
     diff rates of evol in diff genes
      math modeling
character delimitation is straightforward (when u have same genes from diff organisms and align seq, each character in seq alignment is easy to identify)
DNA is ultimate level of info
25
define parsimonious
fewest base changes
26
what does parsimony use
only characters that are informative
27
define informative
have same character in at least 2 diff seq
28
challenges for phylogenetic inference
phylogencis are hypotheses about gene/organism relationship that are constantly updated w/ new data genes can be transferred horizontally from 1 organism to an unrelated on leading to complications genes undergoing selection can be repaidl evoloving and contain many convergently evolving sites diff sires may be evolving at diff rates rearrangements of geneitc mateiral can lead to false conclusions ancient phylo relationships is hard