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General Biology: Tree of Life and Evolutionary Concepts

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이 집합의 용어 (27)

  • What is the Tree of Life?
    A metaphor describing evolutionary relationships among all living organisms, showing how species diverge from common ancestors in a branching pattern.
  • What is a phylogenetic tree?
    A visual hypothesis of the evolutionary history of populations, genes, or species, constructed using data to show relationships among taxa.
  • Define the 'root' of a phylogenetic tree.
    The most ancestral branch in the tree representing the common ancestor of all taxa in the tree.
  • What does a 'node' represent in a phylogenetic tree?
    A point where a branch splits into two or more branches, representing the most recent common ancestor of the descendant groups.
  • What is a polytomy in a phylogenetic tree?
    A node that divides into three or more branches, indicating uncertainty in the evolutionary relationships.
  • Differentiate between ancestral and derived traits.
    Ancestral trait (plesiomorphy): existed in an ancestor; Derived trait (apomorphy): a modified form found in descendants.
  • What is homology?
    Traits shared among taxa due to inheritance from a common ancestor.
  • What is homoplasy?
    Traits that evolved independently in different lineages, often due to similar environmental pressures (convergent evolution).
  • Define a monophyletic group (clade).
    Includes an ancestral species and all its descendants.
  • What is a paraphyletic group?
    Includes an ancestral species and some, but not all, of its descendants.
  • What is a polyphyletic group?
    Does not include the most recent common ancestor of all members.
  • What is the principle of parsimony in tree construction?
    The simplest explanation with the fewest evolutionary changes is preferred.
  • What can branch lengths in phylogenetic trees represent?
    They can represent arbitrary patterns, genetic differences, or evolutionary time between nodes.
  • Explain convergent evolution.
    Independent evolution of similar traits in distantly related organisms due to similar environmental pressures.
  • How does molecular data support whale evolution?
    DNA sequences and SINEs show whales are closely related to hippos within the artiodactyl clade.
  • What is the fossil record?
    The total collection of fossils worldwide, providing direct evidence of past organisms' appearance, location, and age.
  • List limitations of the fossil record.
    Includes habitat bias, taxonomic and tissue bias, temporal bias, and abundance bias.
  • What is radiometric dating?
    A method using radioactive decay to assign absolute dates to events in the fossil record.
  • Name the major eras of the Phanerozoic eon.
    Paleozoic, Mesozoic, and Cenozoic.
  • What is adaptive radiation?
    Rapid production of many descendant species from a single lineage, often after a key trait evolves or new resources become available.
  • What triggered the Cambrian explosion?
    Higher oxygen levels, evolution of predation, new ecological niches, and gene duplications like Hox genes.
  • Define mass extinction.
    Rapid extinction of at least 60% of species within a million years due to catastrophic events.
  • What caused the End-Permian mass extinction?
    Extreme volcanism leading to anoxic oceans, acid rain, and habitat loss.
  • What caused the End-Cretaceous mass extinction?
    Likely an asteroid impact causing wildfires, tsunamis, acid rain, and global cooling.
  • What is the Sixth Mass Extinction?
    The current rapid loss of species driven mainly by human activities like habitat loss and climate change.
  • Define phylogeny.
    The evolutionary history of a group of organisms.
  • What is a clade?
    A monophyletic group including an ancestor and all its descendants.