2.1: Geological Change Over Time

1. Uniformitarianism
   1. States that geological processes that happened in the past can be explained by current geological processes
2. Fossils
   1. Amber
      1. Insects can be caught in sticky tree sap, which can harden and form into fossils
   2. Asphalt
      1. Places that well up with asphalt in sticky pools can trap insects, and harden, like amber
   3. Rock
      1. An animal is quickly buried under sediments and then, decays and become part of a rock
   4. Frozen
      1. An animal is frozen and is preserved well due to the cold temperatures, which can slow decay
   5. Petrified
      1. When an organism's tissues are replaced with minerals
3. Trace Fossils: A fossilized structure that formed in sedimentary rock due to animal activity
   1. Examples:
      1. Footprints
      2. Scat
      3. Burrows