Geologists study rocks to find clues to earth's formation !
Geology is the study of earth's formation and structure!
This changes are driving force behind evolution.
Evidence from rocks and fossils allow us to understand the evolution of life on earth.
How does a fossil form ?
Fossils form when animals die. They decay but sometimes,when the conditions is just right, they converted into fossils.
For example, when a shark dies, sediments are deposited over it's body. After a short time, the shark's soft parts decay,but the teeth do not. Over many years, layers of sediment cover the teeth. Over ore years the layers of sediment are pressed together and become sedimetary rock. The sharks teeth become part of the rock.
Fossils remain within the rock until uncovered through erosion.