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Chapter 26

Phylogeny evolutionary history of a species or group of related species
discipline of systematics classifies organisms and determines their evolutionary relationships
Taxonomy ordered division and naming of organisms
binomial The two-part scientific name of a species
taxon A taxonomic unit at any level of hierarchy
phylogenetic trees Systematists depict evolutionary relationships in branching
branch point represents the divergence of two species
Sister taxa groups that share an immediate common ancestor
rooted tree includes a branch to represent the last common ancestor of all taxa in the tree
basal taxon diverges early in the history of a group and originates near the common ancestor of the group
polytomy branch from which more than two groups emerge
Homology similarity due to shared ancestry
Analogy similarity due to convergent evolution
homoplasies Analogous structures or molecular sequences that evolved independently
Molecular systematics uses DNA and other molecular data to determine evolutionary relationships
Cladistics groups organisms by common descent
clade group of species that includes an ancestral species and all its descendants
monophyletic valid clade; signifying that it consists of the ancestor species and all its descendants
paraphyletic consists of an ancestral species and some, but not all, of the descendants
polyphyletic consists of various species with different ancestors
shared ancestral character a character that originated in an ancestor of the taxon
shared derived character an evolutionary novelty unique to a particular clade
outgroup a species or group of species that is closely related to the ingroup; a group that has diverged before the ingroup
ingroup the various species being studied
Maximum parsimony assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely
maximum likelihood certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events
Orthologous genes found in a single copy in the genome and are homologous between species
Paralogous genes result from gene duplication, so are found in more than one copy in the genome
molecular clock uses constant rates of evolution in some genes to estimate the absolute time of evolutionary change
Neutral theory states that much evolutionary change in genes and proteins has no effect on fitness and is not influenced by natural selection
Horizontal gene transfer the movement of genes from one genome to another
Created by: danat214