Key terms: Lec 1-5 Flashcards
phylogenetic tree
allow us to trace the history changes in morphology, behavior and geographical distribution in a group of organisms
terminal taxa
occur at tips of trees
internal nodes
represent a splitting event
root node
MRCA of all taxa in the tree
cladogram
only the relative branching order is depicted, no meaning to branch lengths
phylogram
branch length is proportional to amount of character change
chronogram
branch length is proportional to time
monophyletic group
includes MRCA and all its descendants
paraphyletic group
includes MRCA but excluding some of its descendants
polyphyletic group
excludes MRCA
clade
monophyletic group
synapomorphy
a trait that evolved in the MRCA of the clade
sister groups
two clades that are each other’s closest relatives
ingroup
the set of taxa under study
outgroup
one or more taxa that fall phylogenetically outside the group under study
convergent evolution
the independent evolution of similar features
reversal
trait disappears and reappears
homology
similarity due to inheritance from a common ancestor
phylogeny and classification
species: binomial name
groups of species: single names and placed in a ranked hierarchy
phylogenetic relatedness
how recently they shared a common ancestor
parsimony informative
two taxa have one state and two taxa have a second state
parsimony uninformative
invariant characters
one taxon different, others all the same
