PRESENTATION OUTLINE
Defenition of a Fossil--The remains or impression of a prehistoric organism preserved as a mold or cast in rock
1st Way a fossil can form-- Cast-
A copy of a fossilized organism made up of minerals
2nd Way a fossil can form-Mold--
Hollow impressions of the fossilized organism
How Fossils are made:
Step 1- The organism dies
Step 2- the organism is covered in mud, sand, etc.
**If the organism is eaten or rots away BEFORE it can be buried, a fossil will not be formed**
Step 3-Lithification-pressure from the accumulating layers of sediment squeeze out excess water in the organism's tissue; soft sediment turns to hard rock
Step 4- Permineralization-minerals from groundwater fill spaces left from the decaying skeleton
Over time, the original organism eventually disappears and is replaced with a copy of the skeleton made up of minerals
As time progresses, the rock encasing the fossil will eventually come to the surface and reveal the fossil
If the fossil is not picked up and saved by someone, it will erode away back to the earth
