Systematics
theory & practice of classifying organisms based on evol history
Phylogeny/Phylogenetic Tree
evolutionary relationships among organisms (common ancestors)
What two primary types of data are used to infer phylogenies?
Morphological data (physical traits) and molecular data (DNA, RNA, protein structures)
In a phylogenetic tree, what does each branch point or node represent?
common ancestor of the two lineages that diverged from that point.
In a phylogenetic tree, what are sister taxa?
2 descendant groups that share immediate common ancestor NOT SHARED with any other group (sibilings)
What is the basal taxon in phylogenetic tree?
line that comes DIRECTLY from root
Where is the root in a phylogenetic tree?
In the beginning
What is a polytomy in phylogenetic tree?
node with more than TWO descendant branches
What is a clade?
group of organisms that includes an ancestor and all of its descendants (living and extinct)l. There can be nested ones.
What is the key difference between a cladogram and a phylogram?
cladogram - branching pattern is important
phylogram - branch lengths indi
Homologous vs. analogous
Homologous = structures are similar
Analogous = inherited from common ancestor
