Chapter 20: Phylogenies and the History of Life

These flashcards cover key concepts related to phylogenies and the classification of life, including classification systems, phylogenetic trees, and evolutionary relationships.

Phylogeny

The evolutionary history and relationship of an organism or group of organisms.

Cladistics

A method of classifying species based on shared derived characteristics into clades.

Horizontal Gene Transfer (HGT)

The transfer of genetic material between unrelated species, prevalent in prokaryotes.

Taxonomy

The science of classifying organisms into taxa based on shared characteristics.

Monophyletic Taxon

A group that includes a common ancestor and all its descendants.

Polyphyletic Taxon

A group that includes species with different ancestors, leaving out a common descendant.

Paraphyletic Taxon

A group that includes an ancestor but excludes one or more descendants.

Linnaean System

A hierarchical classification system created by Carl Linnaeus to categorize organisms.

Rooted Phylogenetic Tree

A tree that represents a common ancestor at its base, showing lineage divergence.

Cladogram

A branching diagram that represents the evolutionary relationships among species.

Endosymbiotic Theory

The theory that mitochondria and chloroplasts originated from the engulfment of prokaryotic cells by ancestral eukaryotic cells.

Shared Derived Character (Synapomorphy)

A trait that arose within a clade and distinguishes members from those that do not share it.

Maximum Parsimony

A principle in cladistics that suggests the simplest explanation or tree that requires the fewest evolutionary changes is preferred.

Homologous Structures

Structures that are similar due to shared ancestry rather than function.

Analogous Structures

Structures that are similar due to convergent evolution, not shared ancestry.

Endosymbiont

A cell that lives inside another cell, with mutual benefits.

Web of Life Model

A model proposing that early prokaryotes exchanged genes, leading to a complex evolutionary history.

Ring of Life Model

A model suggesting that all three domains of life evolved from a genetic pool of prokaryotes swapping genes.

Clade

A branch or lineage on a phylogenetic tree, representing a monophyletic group.