AP Bio - Chapter 20 - Phylogeny

Phylogeny

The evolutionary history of a species or group of related species

Systematics

Discipline that classifies organisms and determines their evolutionary relationships

Taxonomy

The ordered division and naming of organisms

Carolus Linnaeus

Scientist that published a system of taxonomy based on resemblances. The two features of this system that remain useful today are the two-part names for species and hierarchical classification

Binomial

The two-part scientific name for species

Genus

The first part of a specie’s name

Specific Epithet

Second part of the name, is unique to each species within the genus

Name the Taxonomic Groups from Broad to Narrow:

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Taxon

A taxonomic unit at any level of hierarchy

Phylogenetic Trees

Branching diagrams that systematists depict evolutionary relationships

Branch Point

Points in a phylogenetic tree that represent the divergence of two taxa from a common ancestor

Sister Taxa

Groups in phylogenetic trees that share an immediate common ancestor

Rooted Tree

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

Basal Taxon

A phylogenetic tree that diverges early in the history of a group + originates near the common ancestor of the group

Polytomy

A branch from which more than two groups emerge

Analogy

When constructing a phylogeny, systematists need to distinguish whether a similarity is the result of homology or ________

Homology

Similarity due to shared ancestry

Analogy

Similarity due to convergent evolution

Homoplasies

Analogous structures or molecular sequences that evolved independently are also called this

Cladistics

Classifies organisms by common descent

Clade

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

Monophyletic Clade

Valid clades, they consist of the ancestor species and all of its descendants

Paraphyletic Clade

Clade that consists of am ancestral species and some, but not all, of the descendants

Polyphyletic

Clade that consists of various taxa with different ancestors

Shared Ancestral Character

Character that originated in an ancestor of the taxon

Shared Derived Character

Character that is an evolutionary novelty unique to a particular clade

Maximum Parsimony

Principle that assumes that the tree that requires the fewest evolutionary events (appearances of shared derived characters) is the most likely

Molecular Clock

Uses constant of evolution in some genes to estimate the absolute time of evolutionary change