Fossils
- Created by: Clare Parry
- Created on: 09-05-15 09:56
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- FOSSILS
- Evidence for early forms of life come from fossils
- Fossils are the remains of organisms from many years ago and are found in rocks
- dead organisms usually decay
- hard parts don't decay easily
- Hard parts fossilise, e.g. bones and teeth
- conditions don't allow decay e.g. not enough oxygen
- Soft tissues also fossilise e.g. leaf, muscle tissue, animals with no hard parts
- parts of organisms replaced by other materials as they decay
- hard parts don't decay easily
- traces of organisms, e.g. footprints, burrows, rootlet traces
- fossilise in special conditions, e.g. as casts in mud
- FOSSIL EVIDENCE
- The age of a fossil can be worked out from the age of the rock it's in.
- This can show how much or how little organisms have changed over millions of years
- The fossil record is not complete because:
- fossils only form in special conditions
- many early life forms had soft bodies that left few traces
- geological changes in rocks destroy some fossils
- The age of a fossil can be worked out from the age of the rock it's in.
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