chapter 26

What is phylogeny?

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

What is the discipline that classifies organisms and determines their evolutionary relationships?

Systematics.

Who published a system of taxonomy in the 18th century?

Carolus Linnaeus.

What are the two key features of Linnaeus's taxonomy system?

Two-part names for species and hierarchical classification.

What is a binomial?

The two-part scientific name of a species.

What does the first part of a binomial name represent?

The genus.

What is the specific epithet in a binomial name?

The second part of the name that is unique for each species within the genus.

What is the order of taxonomic groups from broad to narrow?

Domain, kingdom, phylum, class, order, family, genus, species.

What is a taxon?

A taxonomic unit at any level of hierarchy.

What is a basal taxon?

A taxon that diverges early in the history of a group and originates near the common ancestor.

What do phylogenetic trees represent?

Patterns of descent, not phenotypic similarity.

What is a sister taxon?

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

What can phylogenetic trees tell us about evolutionary relationships?

They represent hypotheses about evolutionary relationships.

What is a rooted tree in phylogenetics?

A tree that includes a branch to represent the most recent common ancestor of all taxa in the tree.

What does phylogeny provide important information about?

Similar characteristics in closely related species.

How can phylogenies be applied in conservation?

To identify species and determine if they were harvested illegally.

What does it mean when a taxon is not assumed to evolve from the taxon next to it?

Phylogenetic trees do not indicate when species evolved or how much change occurred in a lineage.

What is the significance of the hierarchical classification system introduced by Linnaeus?

It groups species in increasingly inclusive categories.

What is the role of systematists in classification?

They propose classification systems that recognize groups including a common ancestor and all its descendants.