Phylogeny and the Tree of Life

Flashcards covering key vocabulary from the lecture on phylogeny, systematics, phylogenetic trees, and classification of life.

Phylogeny

The evolutionary history of a species or group of species.

Systematics

A discipline focused on classifying organisms and determining their evolutionary relationships, fusing phylogenetics and taxonomy.

Taxonomy

The identification and classification of species.

Binomial Nomenclature

A system developed by Carolus Linnaeus that gives each organism two names (genus and species).

Hierarchical System (Linnaean)

A classification system that arranges life into increasingly inclusive groups, from species up to kingdom.

Scientific Names

Composed of the Genus and Species, written in Latin and shown in italics or underlined.

Phylogenetic Tree

A branching diagram showing evolutionary relationships between organisms.

Branch Points (Nodes)

Represent common ancestors in a phylogenetic tree.

Ancestral Lineage

The line of descent from a common ancestor shown on a phylogenetic tree.

Homology

Likeness between species attributed to shared ancestry (e.g., the forelimbs of vertebrates).

Analogy

Likeness between species due to evolution solving the same problem, not shared ancestry (e.g., wings of insects and birds).

Convergent Evolution

When unrelated species have similar adaptations to a common environment, an example of analogy.

Molecular Systematics

The use of DNA sequences, genomes, and proteins to determine the relatedness of species.

Cladistics

A common approach to systematics where common ancestry is the primary criterion used to classify organisms.

Clade

A group of organisms based on common ancestry.

Shared Derived Characters

An evolutionary novelty unique to a particular clade.

Shared Ancestral Character

A character that originated in an ancestor of the taxon, preceding the divergence of a specific clade.

Maximum Parsimony (Occam's Razor)

A principle stating that the simplest explanation consistent with the facts should be investigated first when building a phylogenetic tree.

Molecular Clock

An approach for measuring the absolute time of evolutionary change based on the observation that some genes and genomic regions evolve at constant rates.

Domain

The highest group of organization for Earth's organisms, based on molecular structure and evolutionary relationships (Bacteria, Archaea, Eukarya).

Bacteria

One of the three domains of life, consisting of prokaryotic cells.

Archaea

One of the three domains of life, consisting of prokaryotic cells that are biochemically similar to eukaryotic cells.

Eukarya

One of the three domains of life, consisting of eukaryotic unicellular and multicellular organisms.