Key Terms
Phylogeny
The evolutionary history and relationships of an organism or group of organisms. It answers "how did this organism come
Taxonomy
The science of classifying organisms into a hierarchical system. It answers "where does this organism fit in the catalog
Systematics
The field that organizes and classifies organisms based on evolutionary relationships. It pulls from fossils, morphology
Memory trick
Did King Philip Come Over For Good Soup?
Three domains
Bacteria, Archaea, Eukarya. Every organism fits into one of these three at the top level.
Two-part scientific name
Genus + species. Rules: Genus is capitalized; species is lowercase.
Full classification for a dog
Eukarya, Animalia, Chordata, Mammalia, Carnivora, Canidae, Canis, lupus.
Subspecies adds a third name
Canis lupus familiaris (domestic dog). Subspecies can interbreed and produce viable offspring but are separated by geogr
Rooted tree
Has a single ancestral lineage at the base. Shows where divergence happened relative to a common ancestor.
Unrooted tree
Shows relationships among species but does not identify a common ancestor.
Branch point (node)
Where one lineage split into two distinct lineages.
Basal taxon
A lineage that branched early from the root and has not diverged significantly since.
Sister taxa
Two lineages that split from the same branch point.
Polytomy
A branch point with more than two lineages. Signals that scientists have not yet resolved all the relationships at that
Trees DO show
The order in which evolutionary events occurred. Which organisms share a common ancestor.