Bio-Ch. 17

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Author:
heidi.tjeerdsma
ID:
217293
Filename:
Bio-Ch. 17
Updated:
2013-05-04 18:14:59
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Intro Bio
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Bio Ch. 17
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  1. What was the earth called before life?
    prebiotic
  2. How old is the earth estimated to be?
    4.5 billion years
  3. How were simple biological chemicals such as amino acids and DNA bases made during early earth?
    using energy from lightning--with no consumers of the chemicals, they can accumulate
  4. What can break down the chemicals, so they collect in areas with less sun?
    ozone
  5. What was probably the first self-replicating molecule?
    RNA
  6. What are the oldest organisms and how old are they?
    • bacteria
    • 3.5 to 3.9 billion years ago
  7. What did bacteria use up?
    hydrogen sulfide from volcanoes
  8. After bacteria used up hydrogen sulfide from volcanoes, what did it use as its source of hydrogen?
    water
  9. What does bacteria start to produce once it develops photosynthesis?
    oxygen
  10. What is proof of oxygen showing up on Earth?
    seeing how old the oldest rust is (rust is oxidized iron)
  11. How long ago did oxygen show up?
    2.3 billion years ago
  12. What did oxygen do to some organisms when it first showed up?
    poisoned some
  13. How long ago did eukaryotes develop?
    1.7 billion years ago
  14. What was the benefit of multicellular organisms?
    their larger size made them harder to eat
  15. How long ago did animals show up?
    600 million years ago
  16. What are advantages to land life?
    • for plants, much stronger sunlight
    • higher amounts of nutrients in soil than in water
    • no predators (yet)
  17. What are the problems for plants on land?
    • need to acquire water--first plants were in wetlands, low to ground
    • used to pollinate using water--new plants used eggs and sperm on the same plant, developed pollen, then seeds, flowers
  18. What were the first animals on land?
    arthropods (insects, spiders, scorpions, crabs)
  19. Why is development of specialized cells important?
    each cell no longer has to do everything, can spend more energy on particular functions
  20. What are skeletons on the outside?
    exoskeleton
  21. What were probably the ancestor for amphibians?
    lobefin fish
  22. What were two things that lobefin fish had that helped them transition to land?
    • primitive lungs
    • fins for crawling
  23. What improvements over amphibians did reptiles have?
    • shelled eggs
    • internal fertilization
    • water resistant skin
  24. What were some advantages for birds and mammals over reptiles?
    • feathers, hair
    • they could remain active at night
    • birds kept feathers and eggs, mammals kept hair, developed live young method of birth
    • birds likely descended from reptilian dinosaurs

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