Flashcards in Phylogenetics Deck (29)
A character with the same state as the ancestor of a group has an ancestral state.
Represent the evolution of taxa over time.
A heritable feature of an organism. Also known as a character trait. How we infer the phylogenetic history of a group.
The form that a character takes.
Branch lengths are proportional to absolute time.
only the order of branching is shown; branch lengths have no meaning.
A hypothesis of homology; all characters are assumed to be homologous unless shown otherwise. (Morphology and behavior are coded numerically; DNA sequence data is coded by nucleotides)
A character with a different state as the ancestor of a group has a derived state.
is similarity due to common ancestry. (Synapomorphies are homologous)
is similarity NOT due to common ancestry. It is due to convergent evolution.
group of taxa you are analyzing
(aka natural group) group of organisms consisting of their MRCA and all of its descendants.
Most Recent Common Ancestor
Represent the MRCA of 2 or more descendants of taxa.
an ancestor that has some but not too much relation to ingroup taxa. Outgroups can be used to discover the starting conditions for your ingroup
include the MRCA but exclude one or more descendants.
the best tree is the one with the fewest # of character changes.
Figures that represent the ancestor-descendant relationships among a group of organisms. (Horizontal, vertical, and circular).
Branch lengths are proportional to amount of genetic change.
Combine organisms that lack a MRCA.
Used when there is uncertainty in the branching pattern. (Soft: used when we have insufficient or conflicting data; hard: used when speciation happened so fast that there are no data that can resolve the relationships(rare))
Leads to root node which is the MRCA of all descendant taxa on the phylogeny.
common ancestral taxa, origin
shows there is an MRCA
Two clades or species that are each other's closest relatives, the two descendant taxa of a single node, originate as lineages at the same time.
The process whereby one species gives rise to two descendant species.
Shared derived state; they define monophyletic groups.
Are at the tips; a taxon is any named group; taxa refers to multiple taxons.