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