Fossils are the remains of plants andanimals from thousands of years ago that are found in rocks
Fossils can tell us how much or how little an organism has evolved
How many ways can fossils form?
3
What's the most common type of fossil formation?
Gradual replacement by minerals
Explain gradual replacement by minerals
Bones that don't decay easily last a long time when buried
they are replaced by minerals as they decay forming a rock hard substance in the shape of the original
surrounding sediment turns to rock but fossil stays distinct
Explain cats and impressions
Organism is buried in soft material like clay
it hardens around organism as it decays leaving a cast
Explain preservation where no decay happens
In amber and tar pits no oxygen or moisture is present so microbes cant decay organisms
in glaciers its too cold for decay to work
peat bogs are too acidic for decay microbes
No one knows how life began because there is no solid, concrete evidence. Many early forms of life were soft bodied and decayed easily. Fossils from millions of years ago have been destroyed by geological activity
