Phylogeny and the Tree of Life Flashcards

A set of vocabulary-style flashcards covering the fundamental concepts of taxonomy, phylogenetics, and cladistics based on the Campbell Biology lecture notes.

Taxonomy

The scientific discipline concerned with classifying and naming organisms.

Binomial Nomenclature

The two-part naming system for species, consisting of the genus and species.

Hierarchical Classification

A system for grouping species in increasingly inclusive categories, ranging from domain to species.

Phylogeny

The evolutionary history of a species or group of related species.

Systematics

The scientific discipline focused on the classification of organisms and the determination of their evolutionary relationships.

Taxon

A specific taxonomic unit at any level of the hierarchical classification system.

Phylogenetic Tree

A branching diagram representing the evolutionary history of a group of organisms.

Branch Point

A point on a phylogenetic tree that represents the divergence of two species from a common ancestor.

Sister Taxa

Groups of organisms that share an immediate common ancestor.

Rooted Tree

A phylogenetic tree that includes a branch representing the last common ancestor of all taxa in the tree.

Basal Taxon

A lineage that diverges early in the history of a group and originates near the common ancestor.

Polytomy

A branch point from which more than two groups emerge, often representing an unresolved pattern of divergence.

Homology

Similarity between organisms that is the result of shared ancestry.

Analogy

Similarity between organisms that is due to convergent evolution rather than shared ancestry.

Convergent Evolution

The process where similar environmental pressures and natural selection produce similar adaptations in organisms from different evolutionary lineages.

Homoplasies

Similar structures that have evolved independently in different lineages; another term for analogous structures.

Molecular Homologies

DNA sequences that are similar between different organisms due to shared common ancestry.

Cladistics

The method of grouping organisms primarily by common descent.

Clade

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

Monophyletic Group

A valid clade consisting of the ancestral species and all of its descendants.

Paraphyletic Group

A group consisting of an ancestral species and some, but not all, of its descendants.

Polyphyletic Group

A grouping that includes several species of varying relatedness 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 that is unique to a particular clade.

Outgroup

A species or group of species closely related to the ingroup being studied, but which diverged before the ingroup species.

Ingroup

The group of species whose evolutionary relationships are being examined in a phylogenetic study.

Maximum Parsimony

The principle which assumes that the tree requiring the fewest evolutionary events is the most likely.

Maximum Likelihood

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

Phylogenetic Bracketing

A technique used to predict features of an ancestor from features found in its descendants.

Horizontal Gene Transfer

The movement of genes from one genome to another through mechanisms such as viral infection, fusion of organisms, or exchange of transposable elements and plasmids.