Transcript Fossils Tell of Long Ago ppt[1]. - KC

Tell of Long Ago
Fossils are animals or plants that
lived a very long time ago.
After they died, they turned to
stone.
How do animals and plants become
fossils when they die?
Most don’t…they just rot
and disappear, often in
swampy forest soil called
peat.
Sometimes leaves fall in the peat. The leaf may
rot away, but the mark of its shape is left.
The peat with the leaf hardens into a
rock, called coal. Coal is a fossil too.
Sometimes animals die and only their
bones are left, covered in mud.
Thousands of years go by, the mud piles
up in layers and the weight of the mud
presses down on the bones. The mud
turns to rock.
As that happens, ground water seeps
through the changing layers of mud.
Minerals are dissolved
in the water.
The water seeps
into all the tiny
holes in the fish
bones.
After a very long time the bones turn
to stone and become a fossil.
Some fossils
are actual parts
of plants or
animals that
have turned to
stone.
Sometimes a fossil is only an imprint of a
plant or an animal.
Not all fossils are found in stone.
Some are found in the frozen ground of
the Arctic, like the bones of the ancient
mammoth.
Millions of years ago, a fly was caught
in the sticky sap of a tree.
The sap hardened and became a
fossil known as amber. The fly
was preserved in the amber.
We can learn many things from
studying fossils.