For the quiz tomorrow

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Fossils are traces of once-living things that are embedded in rocks.

They are buried by layers of sedimentary rock.

Scientists who study early life using fossils are called paleontologists.

They try to come up with ideas as to what the early life was like.

Layers of sediment formed over millions of years is called strata.

How do fossils form.

Fossils are formed when an organism dies and is buried in the ground. The animal decomposes leaving the skeleton behind. After a while, sediments build on top and hardens to rock. The dead organism is eventually buried underneath sedimentary rocks and may come up to the surface millions of years later.

Types of fossils

Petrification- When minerals replace the organic material in a fossil

Molds and Casts- When the organism decays leaving the impression of a mold in the rock.

Carbonization- This is when the more volatile substances are replaced by carbon

Unaltered Preservation- The original material of an organism embedded in amber

Replacement and Recrystallization- When the tissue is replace by another mineral.

Authigenic Mineralization- A cast and mold formation.