Evolutionary Patterns (Exam 2) Terminology

Analogy (Analogous)

Similar traits arising from independent evolutionary paths due to similar environmental pressures, rather than from a common ancestor.

Binomial Nomenclature

A formal system of naming species, consisting of a two-part format including the genus name followed by the species identifier, used universally in scientific contexts.

Character

A heritable attribute or feature of an organism that can be influenced by genetic or environmental factors.

Character State

The specific form or occurrence of a character, describing the status of that character in a given organism, such as a particular flower color.

Cladistics

A method of classification that groups organisms based on shared characteristics that are derived from common ancestry.

Class

A higher taxonomic rank in biological classification that groups together related orders sharing common characteristics.

Domain

The highest taxonomic rank in biological classification, consisting of three major groups: Bacteria, Archaea, and Eukarya.

Family

Taxonomic rank that groups together related genera based on common characteristics.

Genus

A taxonomic category that includes one or more species that are closely related and share a common ancestor.

Geologic Timescale

A system that organizes Earth's history and geological events into a chronological framework, spanning billions of years.

Homology (Homologous)

Traits or structures that are similar in different species due to shared ancestry, even if their functions may differ.

Ingroup

The specific group of organisms being studied or analyzed in a phylogenetic context.

Kingdom

A major taxonomic rank that groups related phyla and serves as a primary classification categorization in biology.

Mass Extinction

A significant and rapid decrease in the biodiversity on Earth characterized by the extinction of a large number of species across multiple taxonomic groups.

Maximum Parsimony

A principle in phylogenetics that suggests the simplest explanation, requiring the fewest evolutionary changes, is usually preferred.

Molecular Systematics

The use of molecular information, particularly DNA sequences, to determine evolutionary relationships and classification among organisms.

Monophyletic Group

A taxonomic grouping that includes a common ancestor and all of its descendants, often referred to as a clade.

Node (Branch Point)

A point on a phylogenetic tree where a single lineage splits into two or more lineages, indicating a common ancestor.

Order

A taxonomic rank that groups together closely related families based on shared traits and evolutionary history.

Outgroup

A taxonomic group that is closely related to, but not part of, the ingroup, used in comparative studies to infer evolutionary relationships.

Phylogenetic Tree

A branching diagram that represents the evolutionary relationships among various biological species based on their physical and genetic characteristics.

Phylogeny

The evolutionary history and lineage of a group of organisms, illustrating how they are related through evolution.

Phylum

A taxonomic rank that groups together related classes sharing a common evolutionary ancestor.

Polytomy

A section in a phylogenetic tree where a node branches out into three or more descendant lineages, indicating uncertainty about the relationships.

Rooted

Describes a phylogenetic tree that has a single common ancestor from which all descendant lineages diverge.

Shared Ancestral Character

A trait that was present in the common ancestor of a group and is retained by all or most descendants.

Shared Derived Character (Synapomorphy)

A characteristic inherited from a common ancestor that sets a group apart from other organisms, defining a clade.

Sister Taxa

Sets of taxa that are more closely related to each other than to any other group, sharing a common ancestor.

Systematics

The scientific study of the diversity of organisms and their evolutionary relationships, encompassing taxonomy and phylogenetics.

Taxon

A group of one or more populations of organisms that a taxonomist judges to be a unit.

Taxonomy

The scientific discipline of naming, describing, and classifying organisms into a system that organizes biological diversity.