Chapter 20

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Chapter 20
2012-04-19 22:37:36
ASTR 205

The Search for Life Beyond Earth- Key terms and concepts
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  1. biological evolution
    the process by which life adjusts itself to changing environments
  2. DNA
    • the long carbon-chain molevule that records information to govern the biological activity of the organism.
    • DNA carries the genetic data passed to offspring
  3. protein
    complex molecule composed of amino acid units
  4. amino acid
    carbon-chain molecule that is the building block of protein
  5. enzyme
    special protein that controls processes in an organism
  6. chromosomes
    a body within a living cell that contains genetic information responsible for the deremination and transmission of hereditary traits
  7. Miller experiment
    an experiment that reproduced the conditions under which life began on Earth and manufactured amino acids and other organic compounds
  8. Cambrian explosion
    a sudden increase in the complexity of life on Earth that signaled the beginning of the Cambrian period
  9. habitable zone
    • a region around a star within which a planet can have temperatures that permit the existence of liquid water
    • also known as the life zone
  10. anticoded
    a message that is designed to be easily decoded
  11. SETI (Search for extra-terrestrial intelligence)
    an exploratory science that seeks evidence of life in the universe by looking for some signatures of its tecnhology
  12. Drake equation
    the equation that estimates the total number of communicaive civilizations in our galaxy