Biology 182 Chapter 26 Terms

Front 1

The evolutionary history of a species or group or related species.

Back 1

Phylogeny

Front 2

A scientific discipline focused on classifying organisms and determining their evolutionary relationships.

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Systematics

Front 3

A scientific discipline concerned with naming and classifying the diverse forms of life.

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Binomial

Front 4

A taxonomic category above the species level, designated by the first word of a species’ two-part scientific name.

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Genus

Front 5

In classification, the taxonomic category above genus.

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Family

Front 6

In classification, the taxonomic category above the level of family.

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Orders

Front 7

In classification, the taxonomic category above the level of order.

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Classes

Front 8

In classification, the taxonomic category above class.

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Phylum

Front 9

A taxonomic category, the second broadest after domain.

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Kingdoms

Front 10

A taxonomic category above the kingdom level.

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Domains – The 3 domains are Archaea, Bacteria, and Eukarya.

Front 11

A named taxonomic unit at any given level of classification.

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Taxon (taxa = plural)

Front 12

A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms.

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Phylogenetic Tree

Front 13

System of classification of organisms based on evolutionary relationships; only groups that include a common ancestor and all of its decedents are named.

Back 13

PhyloCode

Front 14

The representation on a phylogenetic tree of the divergence of two or more taxa from a common ancestor.

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Branch Points – Most Branch points are shown as dichotomies, in which a branch representing the ancestral lineage splits (at the branch point) into two branches, one for each of the two descendent taxa

Front 15

Groups of organisms that share a common ancestor and hence are each other’s closest relatives.

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Sister Taxa

Front 16

Describing a phylogenetic tree that contains a branch point (typically, the one farthest to the left) representing the last of the common ancestor of all taxa in the tree.

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Rooted

Front 17

In a phylogenetic tree, a branch point from which more than 2 descendants taxa emerge.

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Polytomy – A polytomy indicates that the evolutionary relationships among the descendant taxa are not yet clear.

Front 18

Similarity between two species that is due to lack of convergent evolution rather than to descent from a common ancestor with the same trait.

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Analogy

Front 19

Similar (analogous) structure or molecular sequence that has evolved independently in 2 species.

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Homoplasies

Front 20

A scientific discipline that uses nucleic acids or other molecules in different species to infer evolutionary relationships.

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Molecular Systematics

Front 21

An approach to systematics in which common descent is the primary criterion used to classify organisms by placing them into groups called clades.

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Cladistics

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A group of species that includes an ancestral species and all its descendants.

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Clades

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Pertaining to a group of taxa that consists of a common ancestor and all its descendants.

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Monophyletic – A monophyletic taxon is equivalent to a clade.

Front 24

Pertaining to a group of taxa that consists of a common ancestor and some, but not all, of its descendants.

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Paraphyletic

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Pertaining to a group of taxa derived from 2 or more different ancestors.

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Polyphyletic

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A character, shared by members of a particular clade, that originated in an ancestor that is not a member of that clade.

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Shared Ancestral Character

Front 27

An evolutionary novelty that is unique to a particular clade.

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Shared Derived Character

Front 28

A species or group of species from an evolutionary lineage that is known to have diverged before the lineage that contains the group of species being studied.

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Outgroup – An outgroup is selected so that its members are closely related to the group of species being studied, but not as closely related as any study-group members are to each other.

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A species or group of species whose evolutionary relationships we seek to determine.

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Ingroup

Front 30

A principle that states that when considering multiple explanations for an observation, one should first investigate the simplest explanation that is consistent with the facts.

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Maximum Parsimony

Front 31

As applied to systematics, a principle that states when considering multiple phylogenetic hypotheses, one should take into account the hypotheses, one should take into account the hypotheses that reflects the most likely sequence of evolutionary events, given certain rules about how DNA changes over time.

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Maximum Likelihood

Front 32

An approach in which features shared by two groups of organisms are predicted (by parsimony) to be present in their common ancestor and all of its decedents.

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Phylogenetic Bracketing

Front 33

Homologous genes that are found in different species because of speciation.

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Orthologous Genes

Front 34

Homologous genes that are found in the same genome as a result of gene duplication.

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Paralogous Genes

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A method for estimating the time required for a given amount of time required for a given amount of evolutionary change, based on the observation that some regions of genomes appear to evolve at constant rates.

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Molecular Clock

Front 36

The hypothesis that much of evolutionary change in genes and proteins has no effect on fitness and therefore is not influenced by Darwinian natural selection.

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Neutral Theory

Front 37

The transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusions of different organisms.

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Horizontal Gene Transfer

Front 38

A scientific discipline concerned with naming and classifying the diverse forms of life.

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Taxonomy