Chapt 20: Phylogeny and Taxonomy

These flashcards cover the essential vocabulary and definitions related to phylogeny and taxonomy as outlined in the lecture notes.

Phylogeny

The evolutionary history of a species or group of species.

Taxonomy

The scientific discipline of how organisms are named and classified.

Binomial Classification

A 2-part naming system for species, consisting of genus and species, developed by Carolus Linnaeus.

Homologous Organs

Organs that have similar basic structure and shared ancestral lineage but may serve different functions.

Analogous Organs

Organs that perform similar functions but do NOT share a common ancestral lineage.

Molecular Clock

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

Horizontal Gene Transfer

The movement of genes from one genome to another, complicating the tree of life.

Monophyletic Group

A clade consisting of an ancestor species and all of its descendants.

Paraphyletic Group

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

Polyphyletic Group

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

Morphological Homology

Similarities in morphology due to shared ancestry between different species.

Molecular Homology

Similarities in genetic makeup due to shared ancestry between different species.

Cladistics

A method of classifying organisms based on common ancestry and evolutionary relationships.

Branch Point

A point on a phylogenetic tree where lineages diverge.

Sister Taxa

Groups of taxa that share an immediate common ancestor.

Basal Taxon

A lineage that diverges early from all other lineages in its group.

Shared Ancestral Character

A character that originated in an ancestor of the taxon.

Shared Derived Character

An evolutionary novelty unique to a particular clade.

Clade

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

Outgroup

A species or group of species from an evolutionary lineage that is known to have diverged before the lineage that includes the species being studied.

Ingroup

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

Maximum Parsimony

A principle stating that when considering multiple phylogenetic hypotheses, one should first investigate the simplest explanation that is consistent with the facts.

Maximum Likelihood

A method for finding the most likely tree given a specific model of molecular evolution and sequence data.

Polytomy

A branch point from which more than 2 descendant groups emerge, signifying that evolutionary relationships are not yet clear.

Convergent Evolution

The process by which distantly related organisms independently evolve similar traits to adapt to similar environmental pressures.

Taxonomic Ranks

The hierarchical levels of classification: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.