Transcript Ch. 17 Noteguide – The History of Life

Ch. 17 Noteguide –
The History of Life
17.1 The Fossil Record
• Are scientists who study fossils
• Life on Earth. It also shows how different groups
of organisms have changed over time.
• Incomplete, because it takes precise
combinations of conditions
• Extinct
• Precise combinations of conditions
How fossils form:
• Exposure to rain, heat, wind and cold
breaks down existing rocks.
• Minerals replace all or part of the
organisms body.
How scientists determine the age of a fossil:
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Relative dating
Rock layers
Index fossils
Relative dating
2. How Scientists determine the age of a fossil
• Radioactive dating
• Half-life
• Carbob-14 is taken in by living things and
released slowly when they die.
• To determine when the organism lived.
• Carbon-14
• Carbon-12
Geologic Time Scale
• Represent evolutionary time. Places Earth rock
in order by relative age.
• Precambrian
• Time between Precambrian + 3 eras
• Paleozoic
• Mesozoic
• Cenozoic
• Eras that are subdivided
17.2 Earth’s Early History
How did life on Earth Initially begin?
• Heat to melt the entire globe
• The most dense elements form the Earth’s
core.
• The early Earth was much hotter with little
oxygen.
How did life on Earth Initially begin
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27. lots of dissolved iron
28. proteinoid microspheres
29.RNA
30. nucleotides
31. a series of experiments (miller and
Urey)
• 32.microscopic fossils
• 33.oxygen gas
• 34. oxygen for respiration
• 35. proposes that eukaryotic cells arose
from living communities formed by
prokaryotic organisms
• 36. refers to the large scale evolutionary
changes that take place over long periods
of time.
• 37. slow and steady
• 38. horseshoe crab
• 39. rapid evolution
• 40. hox genes