FossilsFossils

What are Fossils?What are Fossils?

Fossils are the remains of plants or Fossils are the remains of plants or animals that lived a long time ago, animals that lived a long time ago, or any evidence of their existence.or any evidence of their existence.

How can Fossils be How can Fossils be Preserved?Preserved?

Unaltered PreservationUnaltered Preservation Altered PreservationAltered Preservation Molds and CastsMolds and Casts Trace FossilsTrace Fossils

Unaltered PreservationUnaltered Preservation

http://web.infoweb.ne.jp/minecity/park/museum/ins_03e.htmlhttp://web.infoweb.ne.jp/minecity/park/museum/ins_03e.html

Insects that got stuck in tree sap were preserved unaltered.

Altered PreservationAltered Preservation

The organism is The organism is preserved but preserved but its original its original skeletal skeletal material is material is altered by altered by chemical chemical changes.changes.

http://www.alertplumbing.com/karls_pics/122500-petrified%20wood.jpghttp://www.alertplumbing.com/karls_pics/122500-petrified%20wood.jpg

Molds and CastsMolds and Casts Molds Molds

A mold forms when something is A mold forms when something is pressed into soft mud and removed by pressed into soft mud and removed by decomposition or pulled out, leaving an decomposition or pulled out, leaving an impression of the object.impression of the object.

Casts Casts A cast is a 3-D representation of A cast is a 3-D representation of

an object from the past. It is an object from the past. It is created when a mold fills up with created when a mold fills up with sediment that hardens.sediment that hardens.

http://www.clas.ufl.edu/users/pciesiel/gly3603c/external.jpghttp://www.clas.ufl.edu/users/pciesiel/gly3603c/external.jpg

Trace FossilsTrace Fossils

http://www.toyen.uio.no/palmus/galleri/montre/x612.jpghttp://www.toyen.uio.no/palmus/galleri/montre/x612.jpg

Trace fossils are Trace fossils are indications that an indications that an organism existed, not organism existed, not the actual organism. the actual organism. They include footprints, They include footprints, nests, tooth marks, nests, tooth marks, worm burrows, root worm burrows, root traces, etc. traces, etc.

Where Where are are

Fossils Fossils Found?Found?

http://necsi.org/projects/evolution/evidence/layers/layers.jpghttp://necsi.org/projects/evolution/evidence/layers/layers.jpg

Why Sedimentary Why Sedimentary Rock?Rock?

http://www.arizonas-vertical-web.com/GrandCanyon/Strata.jpghttp://www.arizonas-vertical-web.com/GrandCanyon/Strata.jpg

Examples Examples of of

FossilsFossils

Sporadoceras Sporadoceras

http://www.imagesco.com/catalog/fossils/

NautilusNautilus

http://www.fmarion.edu/~bio106lab/Resources/nautilus.jpghttp://www.fmarion.edu/~bio106lab/Resources/nautilus.jpg

Orthoceras Orthoceras

http://www.imagesco.com/catalog/fossils/

TrilobitesTrilobites

http://www.imagesco.com/catalog/fossils/

Fossil FishFossil Fish

http://www.imagesco.com/catalog/fossils/

Dinosaur BoneDinosaur Bone

http://www.imagesco.com/catalog/fossils/

BrachiopodsBrachiopods

http://www.itano.net/fossils/belden/brach1.htm

http://www.paxton-plts.org.uk

EchinodermsEchinoderms

http://www.ucmp.berkeley.edu/echinodermata/sdollar.gifhttp://www.ucmp.berkeley.edu/echinodermata/sdollar.gif

http://www.viaccess.net/~jacaroe/star.jpghttp://www.viaccess.net/~jacaroe/star.jpg

Chrinoid StemsChrinoid Stems

http://www.nautiloid.net/fossils/crinoids/crinoid4.jpg

http://www.mpm.edu/reef/racine-crinoid-dior.jpg

http://freespace.virgin.net/craven.pendle/fossils/crinoids/stem_oss.htm

Coral FossilsCoral Fossils

http://www.uky.edu/OtherOrgs/KPS/paleoclass/images/bentleycnidaria1.jpghttp://www.uky.edu/OtherOrgs/KPS/paleoclass/images/bentleycnidaria1.jpg

http://tolweb.org/tree/eukaryotes/animals/cnidaria/malu.jpghttp://tolweb.org/tree/eukaryotes/animals/cnidaria/malu.jpg

Plant FossilsPlant Fossils

http://www.wayne.k12.in.us/scienceworld/rocks_&_fossils.htm

Snails and SlugsSnails and Slugs

http://www.wayne.k12.in.us/scienceworld/rocks_&_fossils.htm

Now it’s time to Now it’s time to make a fossil make a fossil mold and cast!mold and cast!

Fossil MoldsFossil Molds

http://web.ukonline.co.uk/conker/fossils/casts.htm

Sometimes you find a fossil

mold of a shell, like this one. Depending on the shape of

the mold, it is sometimes possible to

make a cast of the shell.

Making a CastMaking a Cast

http://web.ukonline.co.uk/conker/fossils/casts.htm

By filling the mold with plaster, a cast of the fossil can be made. In nature, sediments would fill the mold and

eventually harden, also forming a

cast.

The CastThe Cast

When the plaster dries

it can be separated from

the mold, resulting in two types of fossils, a mold and a

cast.

http://web.ukonline.co.uk/conker/fossils/casts.htm