Evolution of Species

Phylogenic tree (538)

A branching diagram system that represents a hupothesis about the evolutionary hisgory of a group of organisms

Shared ancestral character (543)

A character, shared by members of a particular clade, that originated in an ancestor that is not a member of that clade.

Clades (542)

A group of species that includes an ancestral species and all of its descendants.

Maximum parsimony (544)

A principme that states that when considering multiple explanations for an observation, on should first investigate the simplest explanation that is consistent with the facts.

Taxonomy (537)

A scientific discipline concerned with naming and classifying the diverse forms of life

Systematics (537)

A scientific discipline focused on classifying organisms and determining their evolutionary relationships

Molecular systematics (542)

A scientific discipline that uses nucleic acids or other molecules to infer evolutionary relationships between different species.

Homoplasies (541)

A similar (analogous) structure or moleculare sequence that has evolved independently in two species.

Outgroup (543)

A species or group of species from an evolutionary lineage that is known to have diverged before the lineage that contains the group of species being studied. An outgroup is selected so that its members are closely related to the group of species being studied, but not as closely as any study-group members are to each other.

Ingroup (543)

A species or group of species whose evolutionary relationships we seek to determine.

Genus (plural, genera) (537)

A taxonomic category abive the species level, designated by the first word of a species two-part scientific name

Cladistics (542)

An approach to systematics in which organisms are placed into groups called clades based primarily on common descent.

Shared derived character (543)

An evolutionary novelty that is unique to a particular clade.

Maximum likelihood (545)

As applied to molecular systematics, a principle that states that when considering multiple phylogentic hypothesis, one should take into account the hypothesis that reflects the most likely sequence of evolutionary events, given certain rules about how DNA changes over time.

Rooted (539)

Describing a phylogenetic tree that contains a branch point (often, the one farthest to the left) representing the most recent common ancestor of all taxa in the tree.

Sister taxa (538)

Groups of organisms that share an immediate common ancestor and hence are each other's closest relatives.

Polytomy (539)

In a phylogenetic tree, a branch point from ehich more than two descendant taxa emerge. A polytomy indicates that the evolutionary relationships between the descendant taxa are not yet clear.

Basal taxon (539)

In a specified group of organisms, a taxon whose evolutionary lineage diverged early in the history of the group.

Polyphyletic (543)

Pertaining to a group of taxa derived from two or more different ancestors.

Paraphyletic (543)

Pertaining to a group of taxa that consists of a common ancestor and some, but not all, of its descendants.

Monophyletic (543)

Pertaining to a group of taxa that consists of a conmon ancestor and all of its deescendants a monophyletic taxon is equivalent to a clade.

Linnaean hierarchical classification (537)

Places related genera into the same family, families into orders, orders into classes, classes into phyla (singular, phylum), phyla into kingdoms into domains

PhyloCode(538)

Proposed system of classification of organisms based on evolutionary relationships: only groups that include a common ancestor and all of its descendants are named.

Analogy (540)

Similarity between two species that is due to convergent evolution rather than to descent from a common ancestor with the same trait.

Phylogeny (536)

The evolutionary history of a species or group of related species

Branch points (538)

The representation on a phylogenetic tree of the divergence of two or more taxa from a common ancestor. A branch point is usually shown as a dichotomy in which a branch representing the ancestral lineage splits (at the branch point) into two branches, one for each of the two descendant lineages.

Binomial (537)

The two-part, latinized format of a species, consisting of the genus, and specific epithet; a binomen