Fossils

Definition of a fossil: any ==evidence== of once-living ==organisms== from the distant

past. The ==remains or traces of prehistoric life==. They are ==important components of sediment and sedimentary rocks==.

^^Fossils^^ are the preserved remains of a decomposed object or living thing. They help scientists to look into the past and study the olden earth, like millions of years ago olden earth. Scientists who study fossils are called @@Paleontologists@@.

There are different types of fossils including:

  • Trace Fossils - Fossils that are not actually part of the animal/plant. They tell us information about the organisms %%behaviour%%; how it %%walked%%, if it travelled in a ∗∗herd∗∗**herd**, how it cared for its young, etc. e.g. burrows, borings, footprints, etc.
  • Mold Fossils: e.g. a shell pattern that appears in a rock after a crustacean dies and is buried in mud
  • Cast fossils: A mold fossil that has been filled in with sediment or minerals to create a 3D cast of the organism e.g. a cast of a plant leaf or trilobite
  • True Form Fossils: e.g. fossils, insect in amber, etc.

 

^^Young and Old Rocks^^

  • ^^Young^^ rocks contain @@fossils@@ of more complex %%organisms%%
  • ==Old== rocks @@contain@@ fossils of more simple organismsorganisms

What type of clues can fossils provide about Earth’s history?

  • Organisms behavior, whether they lived in a pack or not, walk speed, etc.

==Types of Fossils and How Its Formed==

  • Trace - when something that is not actually part of the organism is left behind and compressed into dirt or stone e.g. footprints, fossilized feces, fossilized nests
  • Mold - the organism dies and is covered with sediment. It decomposes itself but the sediment hardens around it and leaves an impression e.g. mold fossil of a leaf
  • Cast - a mold fossil that has been filled in with sediment or minerals to create a 3D cast of the organism e.g. cast fossil of an ammonite
  • True Form - fossils of an animal or an organism, when the animal dies and is quickly covered in sediment before it can completely decompose or when volcanic ash covers the organism. Tissues of the organism are replaced with minerals over time e.g. amber insect fossil Fossilized dinosaurs Fossilized fish