FOSSILS:http://perso.menara.ma/dkaraoui1/informations.html
Are the remains of creatures which existed long ago. Fossils range from
thousands of years to many millions of years in age. The earliest
fossils date from around 600 million years ago, however recent reports
suggest bacteria may have existed up to 3 billion years earlier. To put
this in context, the dinosaurs became extinct just 65 million years
ago.
Not all former life was preserved as fossils; in fact the vast majority
simply vanished without trace. The most likely materials to survive
fossilisation are the hard parts such as shells and objects which in
life were constructed from resistant materials, such as Coral. In order
for softer materials to survive, the conditions must be extremely
favourable.
Fossils come in a variety of sizes, from minute traces to large
skeletons. Trace fossils are clues to former life, they result from the
activities or presence of creatures and plants. Examples of these
traces include footprints, burrows and root tunnels. At the larger end
of the scale, fossils also include bones, the largest of which belong
to the dinosaurs, which existed between the Triassic and Cretaceous
periods.
fossils include:
- Shells
- Bones and teeth
- Fossilized footprints and burrows
- Leaves and seeds
- Tree trucks and branches
- Fossilized animal droppings
- The examples used are:
- An ammonite:
A shelled creature that lived in the seas around 150 million years ago.
(To learn more about Ammonites you can cheek ammonite page).
- The Trilobite :
is hard-shelled, segmented creatures that existed over 300 million
years ago in the Earth's ancient seas,
(To learn more about trilobites you can cheek trilobites page).
-Orthoceras:
Fossils are dated back to the Silurian Age 400 + million years ag
http://perso.menara.ma/dkaraoui1/informations.html
http://moroccofossils.tripod.com
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