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General Biology: Evolution, Fossils, and Molecular Genetics

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이 집합의 용어 (21)

  • What is phylogeny in biology?
    Phylogeny is the evolutionary history and relationships among organisms.
  • Define monophyletic group.
    A monophyletic group includes a common ancestor and all its descendants.
  • What distinguishes paraphyletic and polyphyletic groups?
    Paraphyletic groups include some but not all descendants of a common ancestor; polyphyletic groups include organisms from different ancestors.
  • List the Linnaean hierarchy from broadest to most specific.
    Kingdom, Phylum, Class, Order, Family, Genus, Species.
  • How do fossils form?
    Fossils form when organisms are buried in sediment that solidifies into sedimentary rock, preserving remains.
  • What is stratigraphy?
    The study of rock layers (strata) and their fossil content.
  • Explain relative dating in fossils.
    Fossils in lower strata are older than those in upper strata.
  • What is radiometric dating?
    A method to assign absolute ages to rocks and fossils by measuring radioactive isotope decay.
  • Define half-life in radioactive decay.
    The time required for half of a radioactive isotope to decay.
  • What isotopes are used for dating fossils?
    Carbon-14 for up to ~50,000 years; potassium-40 and uranium-238 for older samples.
  • Write the formula for calculating the age of a sample using radioactive decay.
    Age \(t\) is calculated by \(t=\frac{\ln(N_0/N)}{\lambda}\), where λ is decay constant, N₀ initial amount, and N remaining amount.
  • List major events in the history of life on Earth.
    Origin of life (~3.5-4 bya), photosynthesis (~2.7 bya), eukaryotes (~1.8 bya), multicellularity (~1.2 bya), Cambrian explosion (~535-525 mya), land colonization (~450 mya).
  • What are the four key steps in the origin of life?
    1. Abiotic synthesis of organic compounds, 2. Abiotic synthesis of macromolecules, 3. Formation of protocells, 4. Formation of self-replicating RNA molecules.
  • What caused the oxygen revolution and its effects?
    Photosynthesis in prokaryotes increased atmospheric oxygen (~2.4 bya), causing extinction of anaerobes and evolution of aerobic metabolism.
  • How did eukaryotic cells originate?
    Through serial endosymbiosis where prokaryotes were engulfed, forming organelles like mitochondria and plastids.
  • What is microevolution?
    Evolutionary changes within populations or species over short time scales.
  • Define macroevolution.
    Large-scale evolutionary patterns and processes over long time scales, including origin of major groups and mass extinctions.
  • What is plate tectonics?
    Movement of Earth's lithospheric plates altering continents, oceans, climate, and sea levels.
  • What was Pangaea?
    A supercontinent formed by the collision of Earth's landmasses.
  • Describe the genetic basis of the pigeon head crest mutation.
    A single nucleotide mutation (G to T) in the EphB2 gene causes an amino acid change (arginine to cysteine) reversing feather polarity on the head.
  • What is the function of the EphB2 protein?
    A trans-membrane protein involved in cell signaling and development, especially in the nervous system.