Fossils 2 Flashcards
what is the definition of fossil?
any preserved remains of a once living organism
why are fossils important to scientist ?
allows them to build a sequence of evolution of particular organsims
what is a petrified fossil
the turning of something into stone
how is a petrified fossil formed?
water full of minerals seeps into the layers of sediment to reach the dead organism when the water evaporates the minerals harden called perminralisation
how is a mold fossil formed?
when the hard parts of an organism are buried in sediment and then they dissolve leaving a hollow area
how is a cast fossil made?
water with dissolved minerals and sediment fills the molds it then evaporates only leaving the minerals
how are carbon films made?
when an organism dies eventually there will only be carbon left this shows the organisms delicate parts
what is a trace fossil ?
shows the activity of an organism eg footprint set in sediment
what is a preserved remain?
an organism that gets preserved in or close to there original state
what is a preserved remain in amber?
an organism gets trapped in sticky tree resin it then gets covered more
what are preserved remains in tar?
organsims get trapped in a tar pit dies and then the tar soaks into the bones resulting in bones to stop decaying
what are preserved remains in ice?
organism dies in a very cold region its body gets frozen in ice which preserves the organism
what is vital to the formation fossils ?
-organism becomes fossilised when buried
-buried rapidly or in wrong conditions decomposition occurs
-wet and acidic soil dissolves bone
-no oxygen
how are fossils discovered?
- erosion = earth movement and excavation
what is the process of a fossils discovered?
-excavation sites
-sections are marked out
-small handed tools used to remove soil
-soil is sieved
-photographed at each stage
-each item is labelled and catalouged
-fossils clean
