Learn About Fossils
By Anna Guan
How Are Fossils Formed?
First, the animal dies. Second, it is rapidly covered by sediment which is mud or sand. Third,its soft parts rot. Fourth,its hard parts are replaced by minerals. Fifth, at the same time the sediments around it turn into rock. Sixth, years later rocks are removed and it exposes their fossils.
The Fossil Timeline
4.5 BYA: earth forms. 3.8 BYA : first living things. 500 MYA :first vertebrates (fish).400 MYA:first land plants. 360 MYA:first land vertebrates (amphibians). 248 MYA:first mammals appear. 150 MYA:earliest birds. 65 MYA:dinosaurs extinct. 60 MYA:mammals diversify. 2 MYA: ice ages. 160,000 YA:modern humans appear.
Why Are Fossils Important ?
There are many layers of rocks and each layer is older than the layer above. Since evolution is the gradual change in living things over time,fossil layers provide a historical record of the different stages in the evolution of life. And without them we would have no knowledge about how dinosaurs lived and survived.