Phylogeny

What is phylogeny?

The evolutionary history of a species or group of related species, focusing on common ancestors.

What is the discipline of systematics?

Classifies organisms and determines their evolutionary relationships

What is taxonomy?

The ordered division and naming of organisms, developed by Linnaeus.

What is binomial nomenclature?

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

What are the taxonomic groups in hierarchical classification from narrow to broad?

Species, genus, family, order, class, phylum, kingdom, and domain.

What is a taxon?

A taxonomic unit at any level of hierarchy.

What does classification provide for studying organisms?

A way to sort and group organisms for easier study.

What is homology?

Similarity due to shared ancestry.

What is analogy?

Similarity due to convergent evolution.

What are shared derived characters?

Evolutionary novelties unique to a particular clade.

What is a clade?

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

What is the outgroup in phylogenetic studies?

An organism that has diverged before the ingroup and does not share characteristics with it.

What do molecular clocks help track?

Evolutionary time.

How do molecular clocks estimate the absolute time of evolutionary change?

By using constant rates of evolution in genes.

What are potential problems with molecular clocks?

They may be inaccurate if mutations are neutral or favored by natural selection, and estimates older than the fossil record have high uncertainty.

What are the three domains of life in the new classification system?

Bacteria, Archaea, and Eukarya.

What characterizes the domains Bacteria and Archaea?

They are single-celled prokaryotes.

What is the significance of the domain Eukarya?

It includes multicellular organisms and single-celled eukaryotes like protists.

What does a phylogenetic tree or cladogram represent?

Evolutionary relationships and divergence points of taxa.

What is a basal taxon?

The lineage that evolved early from the root and remains unbranched.

What is a sister taxon?

The closest relatives of another given taxa group.

Organisms are classified by their:

• physical structure (how they look)

• evolutionary relationships (relatedness)

• embryonic similarities (embryos)

• genetic similarities (DNA)

• biochemical similarities (processes)