Fossils
- Created by: Sophie O'Donnell
- Created on: 12-05-13 18:45
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- Fossils
- Gradual Replacement
- teeth, bones, shells, don't decay
- instead they are replaced over long periods of time by minerals
- this is how most fossils are formed
- teeth, bones, shells, don't decay
- Casts and impressions
- Things are buried in soft surfaces eg clay
- clay hardens and as creature decays cast is left of where it was
- also footprints can be retained as impressions
- animals burrows can be retained
- Things are buried in soft surfaces eg clay
- Preservation
- If an animal dies in a place where conditions for decay are missing
- eg a peat bog is too acidic
- eg a glacier is too cold
- Decay microbes need oxygen and moisture or they can't work
- If an animal dies in a place where conditions for decay are missing
- can show us how species developed
- show similarities to present day animals
- Untitled
- show similarities to present day animals
- Gradual Replacement
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