AP bio ch 26 vocab

Phylogeny

evolutionary history of a species or group of related species

discipline of systematics

•  classifies organisms and determines their evolutionary relationships

Taxonomy

• scientific discipline concerned with classifying and naming organisms

binomial

two-part scientific name of a species

genus

first part of the name in a binomial

 specific epithet

second part of the binomial

taxonomic groups (broad to narrow)

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

taxon

 taxonomic unit at any level of hierarchy

• phylogenetic tree

evolutionary history of a group of organisms can be represented in a branching visual

branch point

• represents the divergence of two species

Sister taxa

• groups that share an immediate common ancestor

A rooted tree

• a branch to represent the last common ancestor of all taxa in the tree

A basal taxon

• diverges early in the history of a group and originates near the common ancestor of the group

polytomy

• a 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

Cladistics

• groups organisms by common descent

clade

• a group of species that includes an ancestral species and all its descendants

monophyletic

• signifying that it consists of the ancestor species and all its descendants (valid clade)

paraphyletic

• grouping consists of an ancestral species and some, but not all, of the descendants

polyphyletic

• grouping includes distantly related species but does not include their most recent common ancestor

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 group that has diverged before the ingroup

ingroup

the set of closely related taxa (species or groups) currently being studied to determine their evolutionary relationships, typically forming the primary focus of a cladogram.

Maximum parsimony

• assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely

maximum likelihood

• states that, given certain rules about how DNA changes over time, a tree can be found that reflects the most likely sequence of evolutionary events

Orthologous genes

• are 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

Horizontal gene transfer

the movement of genes from one genome to another