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ch.26

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Terms in this set (23)

  • What is a phylogenetic tree?
    A diagram that represents evolutionary relationships among species based on shared characteristics or genetic information.
  • Why can phylogenetic trees be revised?
    Because they are based on current information, and new data or methods can change our understanding of evolutionary relationships.
  • Define a monophyletic group.
    A group consisting of an ancestor and all of its descendants; preferred in taxonomy for reflecting true evolutionary history.
  • What is a paraphyletic group?
    A group containing an ancestor and some, but not all, of its descendants.
  • What is a polyphyletic group?
    A group composed of unrelated organisms descended from more than one ancestor.
  • Why are monophyletic groups preferred in taxonomy?
    Because they accurately represent evolutionary lineages and shared common ancestry.
  • What is the principle of parsimony in phylogenetics?
    Choosing the tree that requires the fewest evolutionary changes or steps.
  • How can neutral mutations spread through populations?
    Through genetic drift, where mutations neither benefit nor harm the organism but can become common by chance.
  • What is a molecular clock?
    A method that uses the rate of genetic mutations to estimate the time since two species diverged.
  • How can horizontal gene transfer complicate phylogenetic trees?
    It introduces genes between unrelated species, obscuring true evolutionary relationships.
  • How does convergent evolution affect phylogenetic analysis?
    It causes unrelated species to develop similar traits, which can be mistaken for shared ancestry.
  • Describe the binomial nomenclature system.
    A two-part naming system for species using genus and species names, e.g., Homo sapiens.
  • What is the hierarchy of taxonomic grouping?
    Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
  • Define phylogeny.
    The evolutionary history and relationships among species or groups of organisms.
  • What is systematics?
    The study of biological diversity and evolutionary relationships.
  • Define taxon.
    A named group of organisms at any level of the taxonomic hierarchy.
  • What are sister taxa?
    Two groups that share an immediate common ancestor.
  • Define analogy in evolutionary biology.
    Similarity in traits due to convergent evolution, not common ancestry.
  • Define homology.
    Similarity in traits due to shared ancestry.
  • What is a clade?
    A group consisting of an ancestor and all its descendants; a monophyletic group.
  • What is a shared ancestral character?
    A trait shared by a group of organisms inherited from a distant common ancestor.
  • What is a shared derived character?
    A trait that evolved in the most recent common ancestor and is unique to a particular clade.
  • Define homoplasy.
    A trait that appears similar in different species but is not due to common ancestry, often from convergent evolution.