Constructing phylogenies Flashcards
(20 cards)
1
Q
phylogeny
A
- a diagram that depicts the lines of evolutionary descent of diff. lineages
- history of a species and relationship with other species
2
Q
taxon
A
- a group of animals that are related at any scale
3
Q
terminal taxa/leaves
A
tips of trees/species
4
Q
nodes
A
branching points
5
Q
root/ancestral node
A
base of tree
6
Q
clade
A
a taxon that consists of all evolutionary descendants of a common ancestor
7
Q
sister species
A
- two species that are each others closest relatives
8
Q
sister clades
A
- two clades that are each others closest relatives
9
Q
cladograms
A
simplified trees with branches all the same length
10
Q
phylograms/chronograms
A
trees with scaled branched lengths
11
Q
traits
A
- characteristics of organisms
- passed down
- occasionally change
12
Q
ancestral traits
A
inherited from common ancestor of group
13
Q
derived traits
A
characteristics unique to specific subgroups
14
Q
homologous traits
A
- a feature shared by taxa descended from a common ancestor
- e.g. vertebral column in all vertebrates
15
Q
synapomorphy
A
- derived traits shared across all members of a group
- e.g. body hair in all mammals
16
Q
autapomorphy
A
- derived trait is unique and defines taxons
17
Q
homoplasies
A
- traits that are superficially similar but not due to shared ancestry
- e.g. flight, echolocation
18
Q
steps to finding morphological
A
- choose terminal taxa (the in-group)
- make observations of characteristics (make presence of traits binary)
- reconstruct all possible trees
- evaluate support for a tree
19
Q
principle of ‘parsimony’
A
- ‘entities should not be multiplied beyond necessity’
- when there are competing theories or explanations, the simpler one is usually more likely true
20
Q
DNA sequence phylogeny
A
- provides more characters
- morphological convergence is common
