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20.1: Key Terms

  • Page ID
    115120
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    analogy
    (also, homoplasy) characteristic that is similar between organisms by convergent evolution, not due to the same evolutionary path
    basal taxon
    branch on a phylogenetic tree that has not diverged significantly from the root ancestor
    binomial nomenclature
    system of two-part scientific names for an organism, which includes genus and species names
    branch point
    node on a phylogenetic tree where a single lineage splits into distinct new ones
    cladistics
    system to organize homologous traits to describe phylogenies
    class
    division of phylum in the taxonomic classification system
    eukaryote-first hypothesis
    proposal that prokaryotes evolved from eukaryotes
    family
    division of order in the taxonomic classification system
    gene transfer agent (GTA)
    bacteriophage-like particle that transfers random genomic segments from one species of prokaryote to another
    genome fusion
    fusion of two prokaryotic genomes, presumably by endosymbiosis
    genus
    division of family in the taxonomic classification system; the first part of the binomial scientific name
    homology
    similarity in characteristics resulting from a shared ancestry
    horizontal gene transfer (HGT)
    (also, lateral gene transfer) transfer of genes between unrelated species
    kingdom
    domain division in the taxonomic classification system
    maximum parsimony
    applying the simplest, most obvious way with the least number of steps
    mitochondria-first hypothesis
    proposal that prokaryotes acquired a mitochondrion first, followed by nuclear development
    molecular systematics
    technique using molecular evidence to identify phylogenetic relationships
    monophyletic group
    (also, clade) organisms that share a single ancestor
    nucleus-first hypothesis
    proposal that prokaryotes acquired a nucleus first, and then the mitochondrion
    order
    class division in the taxonomic classification system
    phylogenetic tree
    diagram that reflects the evolutionary relationships among organisms or groups of organisms
    phylogeny
    evolutionary history and relationship of an organism or group of organisms
    phylum
    (plural: phyla) kingdom division in the taxonomic classification system
    polytomy
    branch on a phylogenetic tree with more than two groups or taxa
    ring of life
    phylogenetic model where all three domains of life evolved from a pool of primitive prokaryotes
    rooted
    single ancestral lineage on a phylogenetic tree to which all organisms represented in the diagram relate
    shared ancestral character
    describes a characteristic on a phylogenetic tree that all organisms on the tree share
    shared derived character
    describes a characteristic on a phylogenetic tree that only a certain clade of organisms share
    sister taxa
    two lineages that diverged from the same branch point
    systematics
    field of organizing and classifying organisms based on evolutionary relationships
    taxon
    (plural: taxa) single level in the taxonomic classification system
    taxonomy
    science of classifying organisms
    web of life
    phylogenetic model that attempts to incorporate the effects of horizontal gene transfer on evolution

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