Phylogenetic Trees Flashcards
What is a phylogenetic tree?
- hypothesized evolutionary relationship among species
- not fact , can’t know relationship without certainty
- always tested / revised
What is the tip of the tree?
Taxa: name can represent pop, species, larger groups , dna
Branches in a tree?
3
- species/ pop/ gene through time
- independent evolutionary lineage from ancestor to descendent
- Length branch meaningless
Internal nodes in trees
- ancestral pop that split into two or more decedents groups
- a speciation event
Root in a tree
Most ancestral branch in tree
Character states ( marks in a tree)
Where think traits arose/got lost in evolutionary history
What is a monophyletic groups
2
An ancestor and all decedents (include internal nodes)
- reflect evolutionary connections
What’s a paraphyletic groups
Include common ancestor and some (not all decedents )
- eg pair pants without a leg
Polyphyletic groups?
Collection organisms where most recents common ancestor not included
What data can be used to build a tree?
7
Morphological, genetic , developmental , Physiological Molecular Behavioral
- homologous trait to indicate relatedness
Homologous traits
Traits from shared ancestor
whale and human hands
Homologous ancestral trait
Inherited from distant ancestor
Homologous derived traits
Appear (mutation ) in most recent ancestor
Synamorphies
3
Shred derive characteristics
More closely related species share more synapomorphies
Unique dna = synapomorphies
Analogous traits (homoplasies )
2
Traits look same but diff ancestor
- due to convergent evolution
Convergent evolution
- adaptation to sim environment evolve similar traits but diff ancestors
What is principal of parsimony
2
- Simplest explanation
- most likely true
What are 5 trees misconceptions?
State them correctly though
1) proximity tips don’t indicate relatedness
2) degree relatedness not indicated by member nodes separating them
3) some taxa at tips are not ancestor to other on tree
4) taxa at end not more evolved then rest
5) evolutionary change don’t always occur at nodes in
