Phylogeny and the Tree of Life

These flashcards cover key terms related to phylogeny and the evolutionary relationships outlined in Campbell Biology.

Phylogeny

The evolutionary history of a species or group of species.

Systematics

An analytical approach to classifying the diversity and determining the evolutionary relationships of living and extinct organisms.

Hierarchical classification

A system where organisms are organized into broader and broader groups.

Taxon

The named taxonomic unit at any level.

Homologous characteristics

Similar traits in different species that arise from a common ancestor.

Binomial nomenclature

A two-part naming system for species, consisting of the genus and specific epithet.

Monophyletic

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

Paraphyletic

A grouping that consists of some, but not all, descendants of a common ancestor.

Polyphyletic

A grouping that includes distantly related species but does not include their most recent common ancestor.

Shared derived character

An evolutionary novelty unique to a particular clade.

Analogy

Similarity due to convergent evolution, not common ancestry.

Molecular systematics

Uses DNA and other molecular data to determine evolutionary relationships.

Molecular clock

A method for measuring the absolute time of evolutionary change using genetic data.

Horizontal gene transfer

The transfer of genes between organisms in different domains.

Cladistics

A method of classification based on common descent.

Outgroup comparison

A method to identify shared derived characters by comparing with an outgroup.

Dichotomies

Two-way branch points in a phylogenetic tree.

Basal taxon

A lineage that diverges early in the history of a group.

Homoplasies

Structures that have evolved independently and are analogous in function.

Phylocode

A system that names groups including a common ancestor and all its descendants.

Maximum parsimony

The principle that suggests scientists should look for the simplest explanation consistent with the facts.

Maximum likelihood

The principle stating that a tree should reflect the most likely sequence of evolutionary events.

Clade

A group that includes an ancestor and all its descendants.

Gene duplication

A process that increases the number of genes in the genome, providing opportunities for further evolutionary change.

Oligogenic

A term for types of genes that arise from single gene duplication events.