fossils

Cards (16)

  • Fossils -are the remains of life that are preserved within sediments and sedimentary rocks.
  • Paleontology -is the study of fossils linking concepts of geology and biology to understand prehistoric life over geologic time.
  • So to produce a fossil, two conditions must be observed: 
    • The organism must possess hard parts (bones, teeth, etc.), and 
    • Rapid burial of the remains increases the chance of preservation. 
  • Permineralization- This occurs when pores and open spaces in tissue (such as bone and wood) are filled with minerals precipitated from mineral-rich solutions such as groundwater.
  • molds and cast- When organisms buried in sediment dissolve or decay away
  • mold- leaves behind hollow space
  • cast- If minerals eventually fill in this hollow space
  • Amber- exceptionally preserved well, often still containing their soft parts.
  •  Carbonization- This happens when these organisms are buried in sediment and eventually dissolve, leaving behind a thin layer of carbon outlining the organism’s shape.
  • Freezing -organisms can also be exceptionally preserved when they are encased in ice.
  • Trace Fossils- can tell a lot about how an organism lived–how it moved, what it ate, and other types of behavior. 
  • geologic time scale (older - younger)
    • hadean eon- formation of the earth
    • archean eon- blue-green algae start to produce
    • proterozoic eon- multicellular life emerges
    • phanerozioc- abundant of animal and plant life existed
  • phanerozoic era (older-younger)
    • paleozoic
    • mesozoic
    • cenozioc
    • 4.6 BYA: Formation of the Earth
    • 530 MYA: Cambrian explosion (sudden appearance of new animals in the fossil record)
    • 11.8 KYA - Present: Holocene; current epoch
  • Absolute vs. Relative Dating
    1. absolute dating- quantitative, gives numerical age [Example: Using radioactive decay (half-life) of a radioactive material to determine the age of a rock]
    2. relative dating- qualitative, arranges object in time [Using a common fossil in two areas (index fossil) to compare what happened at a specific time period
  • geologic time scale (GTS) is a tool geologists use to classify and date rocks and fossils. Instead of numerical ages, time is divided into eons, eras, periods, epochs, and ages