• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
Fossils Lecture
 

Fossils Lecture

on

  • 2,900 views

 

Statistics

Views

Total Views
2,900
Views on SlideShare
2,868
Embed Views
32

Actions

Likes
3
Downloads
137
Comments
1

1 Embed 32

http://www.slideshare.net 32

Accessibility

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel

11 of 1 previous next

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
  • Good job! short and sweet
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Fossils Lecture Fossils Lecture Presentation Transcript

    • Fossils Chapter 21
    • Fossils
      • Remains or traces of once living organisms
      • Tells scientists when, where and how organism lived
      • Formation
        • Normal- Organism decays (deer on road)
        • MUST keep organism from rotting
          • Quick burial (sand, mud, tree sap, etc)
          • Hard parts (bones, wood, etc)
    • Types
    • Petrified Remains
      • Hard, rock-like parts replaced by mineral (calcium)
      • Bones, Tree trunks
    • Carbonaceous Film
      • Carbon Deposits
      • Coal, oil, Natural gas
    • Molds and Casts
      • Remains Covered
      • Sediments Harden
      • Water dissolves object
      • Mold Remains
      • Cast- Sediment fills mold and hardens
    • Original Remains
      • Entire (or part) of organism is preserved
      • Amber (Tree Sap), Ice, Bog (swamp)
    • Trace Fossils
      • Not actually the remains of the organism, but evidence it has been there
      • Footprints, Burroughs, etc
    • How do we figure out age??
      • Absolute Age- Exact age
        • Example 3412 years old or 15 years old
      • Relative Age- Approximate Age
    • Relative Age
      • Best guess of age
      • Index Fossils- Fossils from species that lived for short periods of time and were wide spread across the world
      • Rock Layers-
        • Law of Superposition- “above position”
          • In UNDISTURBED layers of rocks, the oldest layers are on the bottom and younger layers on top
          • Think about a clothes hamper
    • Geode
    • Absolute Dating
      • True Age
      • Radioactive Decay- Breakdown of unstable isotopes into stable atoms
      • Isotope- Variation in number of neutrons in an atom’s nucleus
      • Carbon- 2 isotopes
        • C 12 - 6p and 6 n=12
        • C 14 - 6p and 8n=14
        • C 14 is unstable
    • Radiation
      • Alpha ( α )- blocked by newspaper
        • 2(p + )&2n=mass# decrease by 4, atomic # decrease by 2
      • Beta ( β )- Blocked by brick wall
        • 1 e -= no change in mass #
        • Electron is from neutron (p& e - )causing Atomic # to increase by 1
      • Gamma ( γ ) Blocked only by lead!
        • Photon
    • Isotopes
      • Unstable- Parent isotope
      • Stable- Daughter
    • Half-Life
      • Amount of time needed to breakdown half of the parent material into daughter material
      • Carbon 14- 5730 years
      • Uranium- 4.5 billion years
      • Potassium 40- 1.3 billion years
      • Which would you use to date the planet?