Chapter 2: The Tree of Life

Parsimony

Parsimony

________ is the principle of accounting for observations by the hypothesis requiring the fewest or simplest assumptions that lack evidence.

Horizontal gene transfer

_________ is the movement of genetic material between unicellular or multicellular organisms other than by the "vertical "transmission of DNA from parent to offspring (reproduction).

Paralogous

________ refers to genes that originate from ancestral gene duplication.

Anagenesis

________ is the evolutionary change of features within a single lineage (species)

Vestigial characters

________ are traits or structures that do not seem to have a purpose but are still there.

homologous

The forelimb bones of tetrapod vertebrates are all ______ with one another.

lineage

Each branch in a phylogenetic tree is called a ________.

Cladogenesis

________ is the branching of a lineage into two or more descendent lineages.

Orthologous

________ refers to genes that diverge from a common ancestral gene by phylogenetic splitting at the organismal level.

Hybrid speciation

________ is when various phenotypic features and DNA markers throughout the genome reveal two ancestral sources.

Hierarchical classification

________ is a method of categorizing groups of organisms.

Fossils

________ can provide important information about the evolutionary history of a group, but many organisms do not leave these, so phylogenies are mostly inferred from living organisms.

Homologous characters

________ are features among species that have been inherited from common ancestors.

Homoplasy

________ is the independent evolution of a character or character state in different taxa.

Phylogeny

________ is the history of the events by which species or other taxa have successively arisen from common ancestors.

species

A(n) ________ evolves, not as a whole, but piecemeal, with each feature evolving independently from the others.

Mosaic evolution

________ is the evolution of different characters at different rates within a lineage.

root

A ______ is the lineage leading to the most recent common ancestor of all the species in the phylogeny.

Evolutionary reversal

________ is the evolution of a character from a derived state back toward a condition that resembles an earlier state.

Binomial nomenclature

________ is a system of two- part names consisting of a genus name and a specific epithet (ex: Homo sapiens)

Sister groups

________ are two clades that originate from a common ancestor.

polyphyletic taxon

A(n) ________ includes species that do not exclusively share a common ancestor.

Parallelism

________ is the evolution of similar or identical features independently in related lineages, thought usually to be based on similar modifications of the same developmental pathways.