Biology 130 Chapter 20

shared ancestral character

describes a characteristic on a phylogenetic tree that is shared by all organisms on the tree

shared derived character

describes a characteristic on a phylogenetic tree that is shared only by a certain clade of organisms

genus

division of family in the taxonomic classification system; the first part of the binomial scientific name

systematics

field of organizing and classifying organisms based on evolutionary relationships

sister taxa

two lineages that diverged from the same branch point

basal taxon

branch on a phylogenetic tree that has not diverged significantly from the root ancestor

polytomy

branch on a phylogenetic tree with more than two groups or taxa

monophyletic group

(also, clade) organisms that share a single ancestor

analogy

(also, homoplasy) characteristic that is similar between organisms by convergent evolution, not due to the same evolutionary path

maximum parsimony

applying the simplest, most obvious way with the least number of steps

phylogenetic tree

diagram used to reflect the evolutionary relationships among organisms or groups of organisms

order

division of class in the taxonomic classification system

kingdom

division of domain in the taxonomic classification system

phylum

division of kingdom in the taxonomic classification system

family

division of order in the taxonomic classification system

class

division of phylum in the taxonomic classification system

The different levels of the taxonomic classification system are:

domain, kingdom, phylum, class, order, family, genus, species

phylogeny

evolutionary history and relationship of an organism or group of organisms

taxonomy

science of classifying organisms

rooted

single ancestral lineage on a phylogenetic tree to which all organisms represented in the diagram relate

taxon

single level in the taxonomic classification system

binomial nomenclature

system of two-part scientific names for an organism, which includes genus and species names branch point

cladistics

system used to organize homologous traits to describe phylogenies

molecular systematics

technique using molecular evidence to identify phylogenetic relationships