Classification and Systematics

Vocabulary flashcards covering classification history, taxonomy, tree reading, monophyletic/paraphyletic/polyphyletic groups, homology, homoplasy, symplesiomorphies, synapomorphies, and parsimony.

Scala naturae

Aristotle's concept of nature visualised as a ladder where species are arranged according to their complexity.

Taxonomy

A formal system for naming and classifying species into hierarchical categories.

Binomial nomenclature

A standardized system for naming species using a two-part format consisting of the Genus followed by the Species identifier (e.g., Canis lupus).

Phylogeny

The evolutionary history of a species or group of organisms.

Systematics

The scientific discipline focused on classifying organisms and determining their evolutionary relationships.

Phylogenetic tree

A hypothesis that illustrates ancestor-descendant relationships among various taxa.

Topology

The specific branching structure and arrangement of branches on a phylogenetic tree.

Monophyletic group

A group consisting of a common ancestor and all of its descendants.

Paraphyletic group

A group consisting of a common ancestor and some, but not all, of its descendants.

Polyphyletic group

A group that does not include the most recent common ancestor of all the organisms within it.

Homologous characters

Traits inherited from a common ancestor that reflect evolutionary relationships and may be modified over time.

Homoplasious characters

Analogous traits shared by species that do not share a common evolutionary origin, arising independently through convergent evolution.

Symplesiomorphies

Shared ancestral characters that occur in members of a group as well as their common ancestor(s).

Synapomorphies

Shared derived characters that are unique to a particular clade.

Principle of parsimony

The rule of tree construction stating that the simplest hypothesis, requiring the fewest evolutionary steps, is the most likely.