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General Biology: Evolution, Phylogeny, Prokaryotes, and Eukaryotes

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Terms in this set (29)

  • Abiotic synthesis
    The formation of organic molecules from inorganic precursors without biological activity, a key step in the origin of life.
  • RNA world hypothesis
    The idea that early life used RNA both to store genetic information and to catalyze chemical reactions before DNA and proteins evolved.
  • Protocell
    A simple, cell-like structure with a membrane that exhibits some characteristics of life, such as maintaining an internal environment.
  • Radiometric dating
    A method to determine the age of fossils by measuring the decay of radioactive isotopes and calculating based on half-life.
  • Endosymbiosis
    A theory that explains the origin of eukaryotic cells as a result of one prokaryote living inside another, leading to organelles like mitochondria.
  • Mass extinction
    A widespread and rapid decrease in biodiversity caused by catastrophic events, distinct from background extinction.
  • Adaptive radiation
    The rapid evolution of many species from a common ancestor when new ecological niches become available.
  • Heterochrony
    An evolutionary change in the timing or rate of developmental events, affecting organism morphology.
  • Phylogenetic tree
    A diagram showing evolutionary relationships among species based on common ancestry.
  • Homology
    Similarity in traits due to shared ancestry.
  • Analogy
    Similarity in traits due to convergent evolution, not common ancestry.
  • Clade
    A group of organisms that includes an ancestor and all its descendants, representing a monophyletic group.
  • Maximum parsimony
    A principle that the simplest phylogenetic tree with the fewest evolutionary changes is preferred.
  • Prokaryote
    A unicellular organism lacking a nucleus and membrane-bound organelles, including bacteria and archaea.
  • Gram-positive bacteria
    Bacteria with thick peptidoglycan cell walls that retain the crystal violet stain in Gram staining.
  • Endospore
    A resistant, dormant structure formed by some bacteria to survive harsh conditions.
  • Binary fission
    A form of asexual reproduction in prokaryotes where one cell divides into two genetically identical cells.
  • Horizontal gene transfer
    The movement of genetic material between organisms other than by descent, increasing genetic diversity.
  • Obligate anaerobe
    An organism that cannot survive in the presence of oxygen.
  • Endosymbiotic theory evidence
    Mitochondria and chloroplasts have their own DNA, double membranes, and reproduce independently, supporting their origin from prokaryotes.
  • Excavata
    A eukaryotic supergroup including protists like Giardia and Euglena, characterized by modified mitochondria and unique flagella.
  • SAR supergroup
    A diverse eukaryotic clade including Stramenopiles, Alveolates, and Rhizarians, important in aquatic ecosystems.
  • Diatoms
    Photosynthetic stramenopiles with silica cell walls that contribute significantly to global carbon fixation.
  • Dinoflagellates
    Alveolates with two flagella causing spinning movement; some cause harmful red tides.
  • Archaeplastida
    A eukaryotic supergroup including red algae, green algae, and land plants, characterized by primary plastids.
  • Amorpheans
    A eukaryotic supergroup including amoebozoans and opisthokonts, distinguished by unique pseudopodia or flagella.
  • Convergent evolution
    The independent evolution of similar traits in unrelated lineages due to similar environmental pressures.
  • Mutualism
    A symbiotic relationship where both species benefit.
  • Paedomorphosis
    An evolutionary process where adults retain juvenile features of their ancestors.