Ch. 26: Phylogeny and the Tree of Life: Classification and Evolution

Phylogeny

Study of evolutionary relationships among species.

Tree of Life

Diagram representing evolutionary history of organisms.

Species Categorization

Process of classifying organisms into groups.

Biologists

Scientists who study living organisms and their relationships.

Phylogeny

Evolutionary history of a species or group.

Systematics

Discipline classifying organisms and their relationships.

Convergent Evolution

Independent evolution of similar traits in species.

Binomial Nomenclature

Two-part naming system for species.

Carolus Linnaeus

Published taxonomy system in the 18th century.

Genus

First part of a species' scientific name.

Specific Epithet

Unique second part of a species' name.

Hierarchical Classification

Grouping species in increasingly inclusive categories.

Taxon

Group at any level of classification hierarchy.

Phylogenetic Tree

Diagram representing evolutionary relationships among organisms.

Sister Taxa

Groups sharing a common ancestor not shared by others.

Rooted Tree

Tree including a branch for the most recent ancestor.

Basal Taxon

Lineage diverging early in a group's history.

Homologies

Similarities due to shared ancestry in organisms.

Morphological Divergence

Great structural differences despite genetic similarity.

Analogy

Similarity due to convergent evolution, not ancestry.

Cladistics

Grouping organisms by common ancestry.

Clade

Group including an ancestor and all descendants.

Monophyletic Group

Includes an ancestor and all its descendants.

Paraphyletic Group

Includes an ancestor and some descendants.

Polyphyletic Group

Includes distantly related species without a common ancestor.

Shared Ancestral Character

Character originating in an ancestor of the taxon.

Shared Derived Character

Evolutionary novelty unique to a particular clade.

Outgroup

Species closely related but not part of the ingroup.

Molecular Clock

Estimates time of evolutionary change using genetic data.

Maximum Parsimony

Tree requiring fewest evolutionary events is preferred.

Maximum Likelihood

Identifies most probable tree based on DNA data.

Genome Evolution

Lineages share many orthologous genes over time.

Horizontal Gene Transfer

Movement of genes between different genomes.

Three-Domain System

Classifies life into Bacteria, Archaea, and Eukarya.

Eukarya

Domain including organisms with true nuclei.

Lokiarcheaota

Recently discovered group possibly sister to eukaryotes.

Fossil Record

Provides data for calibrating molecular clocks.

Phylogenetic Bracketing

Predicts features shared by closely related groups.

Transposable Elements

DNA segments that can move within genomes.

Plasmids

Small DNA molecules within cells, separate from chromosomal DNA.