What are fossils
Millions of years ago, when animals, fish and plants died, sometimes their remains were quickly covered by dust, ice, mud, sand or even lava from active volcanoes. This would protect them from the elements and preserve their shape for millions of years; the result is a ‘Fossil’.
Types of Fossil
Body Fossils include bones, shells, claws and teeth from animals. This group also includes leaves, seeds and cones from plants, and even whole trees.
Scientists have also discovered fossils of animal footprints, eggs and nests which provide information about how animals and plants lived long ago.
How does fossil forms?
Millions of years ago, when animals, fish and plants died, sometimes their remains were quickly covered by dust, ice, mud, sand or even lava from active volcanoes. Over time decomposition took place as bacteria slowly ate through any soft parts, leaving harder elements like shells, teeth, bones and claws. Cavities in the remains became infused with mineral-rich water which seeped through the sediment layers, replacing the original minerals of the animal or plant with new minerals (mostly a silicate, such as quartz), creating rock-like copies of skeletons, leaves and even tree, preserving their shape for millions of years. This process is called permineralization and the result is a fossil.
Let’s look at some special ways that fossils can be created
If a tree has a cut it releases an orange liquid called SAP. This is so sticky that if an insect walked across it in the past, it would have been stuck forever. Over millions of years this SAP will have turned into an Amber Fossil with the insect preserved inside.
Inside all plants and animals there is a chemical called carbon. Sometimes as they decomposed this carbon leaves an imprint in the ground.
Sometimes whole animals have been found preserved in ice, and look exactly the same as they did when they died.
Significance of Fossil
Once the world was covered in ice and fossils protected deep underground. As the ice melted, it formed rivers, which eroded the earth, uncovering the fossilized remains from animals and plants. Many fossils are found where the sea once was, or now is, as the water erodes the sediment below. Scientists have discovered complete fossilized animals and trees dating from millions of years ago, and these can teach us about life long before mankind.