Phylogenetics and Systematics

A set of flashcards covering key vocabulary and concepts from the lectures on phylogenetics and systematics.

Phylogenetic tree

A diagram that represents a hypothesis about evolutionary relationships between species or taxa.

Phylogeny

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

Systematics

The scientific discipline that classifies organisms and determines their evolutionary relationships.

Homology

Phenotypic and genetic similarities due to shared ancestry.

Analogy

Similarity between organisms due to convergent evolution, not shared ancestry.

Biological classification system (Taxonomy)

A hierarchical structure used to organize and differentiate organisms based on shared characteristics.

Cladistics

A method of classifying organisms based on common ancestry.

Clade

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

Shared derived character

An evolutionary novelty unique to a particular clade.

Outgroup

A species or group that is closely related to the ingroup and helps define characteristics of the ingroup.

Molecular clock

A method that uses constant rates of evolution in some genes to estimate the absolute time of evolutionary change.

Orthologous genes

Genes found in a single copy in the genome and homologous between species, diverging after speciation.

Paralogous genes

Genes that are found in more than one copy in the genome due to gene duplication.

Maximum parsimony

A principle that states the tree requiring the fewest evolutionary changes is the most likely.

Binomial nomenclature

A two-part scientific name for species, consisting of the genus name and a specific epithet.

Sister taxa

Groups that share an immediate common ancestor not shared by any other group.

Basal taxon

The species that diverges early in the history of a group and is near the common ancestor.

Homoplasy

A character shared by a set of species that is not present in their common ancestor.

Fossil record

Historical evidence used to trace the evolution of species based on physical remains.

Convergent evolution

The independent evolution of similar features in species of different lineages due to similar environmental pressures.

Phylogenetic bracketing

A method that infers characteristics of ancestors based on their descendants.