fossils

• what are fossils?


  fossils are the 'remains' of organisms from millions of years ago which are formed in rocks
• fossils can be formed from parts of organisms that have not decayed because of

  one or more of the conditions needed for decay being absent
• fossils can be formed when parts of the organism are replaced by

  minerals when they decay
• fossils can be formed as preserved organisms such as

  footprints, burrows and rootlet traces
• scientists have used fossils to look how organisms have

  gradually changed over long periods of time
• why are fossil records incomplete?

  a lot of life forms were soft-bodied and so didn't leave behind many noteworthy traces

  geological activity has also caused the destruction of many traces of ancient life

  because of this scientists cannot be certain about the origins of early life