Paleogeology

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Paleogeology

• Paleontology Geology

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Paleontology

• The study of fossils

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Geology

• The study of the origin, history and structure of
  the Earth.

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Paleogeology

• Combines the studies of paleontology and geology
• Go to Becoming Human.org and view Explore A Dig

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How Fossils Form

• Organism is quickly covered with sediment.

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Fossil Formation

• 2. Minerals from the sediments seep into the
  body.

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Fossil Formation

• 3. Additional layers of sediment compress,
  forming rock.
• 4. Minerals eventually replace all the bodys
  bone material.

Animation
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How are fossils discovered?

• Earth movements or erosion may expose the fossil
  millions of years after formation.

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Dating Fossils

• 2 Methods
• Indirect Dating
• Does not determine the exact age
• Direct Dating
• Determines a number

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Indirect Dating

• Gives a relative age of a fossil
• Younger than, older than
• Strata Layers of Earth

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Stratigraphy

• Determining the relative age of a fossil based on
  which layer its found in.
• Top Younger
• Bottom Older

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Horse Evolution
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Our understanding of the evolution of horse feet,
so often depicted in textbooks, is derived from a
scattered sampling of horse fossils within the
multi-branched horse evolutionary tree. These
fossil organisms represent branches on the tree
and not a direct line of descent leading to
modern horses. But, the standard diagram does
clearly show transitional stages whereby the
four-toed foot of Hyracotherium, otherwise known
as Eohippus, became the single-toed foot of
Equus. Fossils show that the transitional forms
predicted by evolution did indeed exist.
To learn more about fossil horses on this
continent view the video interview with Dr.
Michael Voorhies.
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Direct Dating

• Can determine an age of the fossil
• Gets you a specific number of years old.

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Radiometric Dating

• Uses radioactive isotopes
• Atoms with unstable nuclei that break down
  (decay) over time.
• Forms a new isotope after it decays.
• Age is determined by comparing the amount of the
  original isotope to the new isotope.
• If you know the half-life of the original
  isotope, you can determine the age.

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Example

• A rock forms that contains a radioactive isotope
  that has a half-life of 1 million years.
• Today, the rock contains equal amounts of the
  original and new isotopes.
• The age of the fossil is..?
• 1 MILLION YEARS!

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Other Resources

• www.becominghuman.org