Chapter 20 Flashcards
Phylogeny
The evolutionary history of a species or group of related species.
Systematics
Classifies organisms and determines their evolutionary relationship.
Taxonomy
The scientific discipline responsible for the ordered division and naming of organisms.
Binomial
The two part format of scientific species names.
Genus
First part of a species’ scientific name.
Taxonomic Groups
genus, family, order, class, phylum, kingdom, domain
Taxon
A named taxonomic unit at any level of the hierarchy.
Phylogenetic Tree
Branching diagrams that represent evolutionary relationships.
Branch Point
The divergence of two evolutionary lineages from a common ancestor on a phylogenetic tree.
Sister Taxa
Groups that share an immediate common ancestor not shared by any other group.
Rooted Tree
Includes a branch to represent the most recent common ancestor of all taxa in the tree.
Basal Taxon
A lineage that diverges from all members of its group early in the groups history.
Analogy
Similarity between species due to convergent evolution.
Clade
A group of species that includes an ancestral species and all its decendents.
Monophyletic group
Consisting of the ancestor species and all its decedents.
Paraphyletic group
Consists of an ancestral species and some, but not all, of the decendents.
Polyphyletic group
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.
Ingroup
The group of species being studied.
Outgroup
A species or group of species closely related but not part of the ingroup.
Maximum Parsimony
Assumes that the most likely tree is the one that requires the fewest evolutionary events.
Molecular Clock
Uses the constant rate of evolution observed in some genes to estimate the absolute time of evolutionary change.
Horizontal Gene Transfer
The transfer of genes from the genome of one species to another. Caused by the exchange of transposable elements/plasmids, viral infection or fusion of organism.
Cladogram
A diagram used to represent a hypothetical relationship between groups of animals.
Homoplasy
A character shared by a set of species but not present in their common ancestor.
Polytomy
An internal node of a phylogenetic tree in a rooted tree linked to three or more child subtrees or in an unrooted tree and attached to four or more branches.
