Fossils
Fossils
Definition:A fossil is the preserved remains, impression, or trace of a plant or animal that lived millions of years ago. Fossils are usually found in rocks.
How fossils are formed
A plant or animal dies.
It is buried by mud, sand, or ash.
Over millions of years, more layers build up.
The layers become rock.
Minerals replace or fill the remains.
The preserved remains become a fossil.
Types of fossils
Body fossils – The actual remains of living things.
Bones
Teeth
Shells
Leaves
Wood
Trace fossils – Signs that an organism was there.
Footprints
Burrows
Nests
Eggs
Droppings (called coprolites)
Where are fossils found?
Sedimentary rocks
Riverbeds
Deserts
Cliffs
Mountains
Quarries
Why are fossils important?
Fossils help scientists:
Learn about plants and animals that lived long ago.
Understand how Earth has changed.
Find the age of rocks.
Study evolution (how living things change over time).
Learn about ancient climates and environments.
Conditions needed for fossil formation
The organism must be buried quickly.
It should have hard parts like bones or shells (though some soft parts can be preserved in rare cases).
Oxygen should be limited to slow decay.
Enough time—usually millions of years.
Interesting facts
Most living things do not become fossils.
Fossil formation is very rare.
Some fossils are more than 3.5 billion years old.
Scientists who study fossils are called paleontologists.
Examples of fossils
Dinosaur bones
Mammoth teeth
Shells
Leaf impressions
Fish fossils
Dinosaur footprints
Fossil eggs