Phylogeny and the Tree of Life Vocabulary Flashcards

Vocabulary flashcards focusing on key biological terms, classification rules, phylogenetic tree components, cladistics, character states, and parsimony based on Chapter 26 lecture notes.

Biodiversity

The variety of life on Earth.

Taxonomy

The naming and grouping of organisms.

Systematics

The biological discipline focused on classifying organisms and determining their evolutionary relationships.

Phylogeny

The evolutionary history and relationship of a species or group of organisms.

Taxon

Any named group of organisms at any level of the biological hierarchy, such as Mammalia or Panthera.

Clade

A group of organisms consisting of an ancestral lineage plus all of its descendants.

Binomial Nomenclature

A two-part naming system for species consisting of a capitalized Genus name followed by a lowercase species epithet.

Carl Linnaeus

The 1700s father of modern taxonomy who standardized the biological naming system and hierarchical classification.

Linnaean Hierarchy

A nested ranking structure of increasingly inclusive categories: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

Archaea

A domain of prokaryotic organisms distinct from Bacteria, often including extremophiles, that are genetically more closely related to Eukarya.

Eukarya

The domain of organisms whose cells contain a nucleus, encompassing protists, fungi, plants, and animals.

Homology

Phenotypic and genetic similarities between organisms due to shared ancestry.

Analogy

Similarities between organisms that are due to convergent evolution rather than shared ancestry.

Convergent Evolution

The process where similar environmental pressures or natural selection produce similar traits in different evolutionary lineages.

Phylogenetic Tree

A branching diagram (also called a dendrogram) representing a hypothesis about the evolutionary history and relationships of organisms.

Root

The ancestral population on a phylogenetic tree from which all other species in the diagram originate.

Node

A branching point on a phylogenetic tree representing the most recent common ancestor of descendant lineages.

Branch

A line on a phylogenetic tree representing an evolutionary lineage over time.

Sister Taxa

Groups of organisms that share a common ancestor that is not shared by any other group, making them each other's closest relatives.

Cladistics

A method of biological classification based on ancestry that organizes species into nested groups called clades.

Monophyletic Group

A group that consists of an ancestral species and all of its descendants, forming a true clade.

Paraphyletic Group

A group consisting of an ancestral species and some, but not all, of its descendants.

Polyphyletic Group

A group consisting of organisms from different lineages where the most recent common ancestor of its members is not included in the group.

Ancestral Character

A trait that was already present in an earlier ancestor of a group.

Derived Character

A trait that evolved later in a lineage from the ancestral condition.

Shared Ancestral Character

An ancestral trait shared by multiple taxa that originated prior to the common ancestor of the group, such as the backbone in mammals.

Shared Derived Character

A new trait shared by multiple descendants of a common ancestor that evolved in that ancestor, such as hair in mammals.

Plesiomorphy

An ancestral trait retained within a lineage.

Apomorphy

A general term for a newly evolved derived trait that differs from the ancestral condition.

Synapomorphy

A shared derived trait inherited from a common ancestor that serves as evidence for grouping taxa into the same clade.

Autapomorphy

A derived trait unique to a single lineage that distinguishes it from others but does not group it with other organisms.

Homoplasy

A similar trait that evolved independently in different lineages, often through convergent evolution.

Outgroup

A species or group closely related to the ingroup being studied, used as a reference to determine whether character states are ancestral or derived.

Ingroup

The primary group of species being studied and evaluated for evolutionary relationships.

Maximum Parsimony

A principle used to evaluate phylogenetic trees that favors the tree hypothesis requiring the fewest evolutionary changes.