PowerPoint Presentation

Fossils: Windows into the PastEssential Question:Explain the use of fossils as evidence of Earths history and its life forms.Vocabulary PaleontologyFossilFossil RecordMoldCastPetrifiedPreservedCarbonizedTraceTrilobite

ConceptUses of FossilsTypes of FossilsPaleontologyThe study of fossil evidence to learn about ancient life forms.

FossilThe preserved remains of organisms that lived in the distant past.Can also be evidence of organisms behaviors that were preserved.

Fossil RecordThe evidence provided by fossils about what Earth was like millions of years ago.Clues provided include:Climate & atmosphere changes.Geology plate tectonics, erosion.Diversity of life on Earth different organisms that have lived and how they have changed.

#1 Mold FossilSediments bury an organism and change into rock. Over time the organism decays and leaves a cavity (hole) in the shape of the organism.

#2 Cast Fossil When a mold fossil is filled with sand or mud that hardens into the shape of the organism.

#3 Petrified Fossil When minerals soak into buried remains, replace the remains, and then change into rock.

#4 Preserved Fossil Forms when organisms do not decay at all because they are trapped in ice, tar, or amber.

#5 Carbonized FossilBody parts like leaves, stems, and flowers are pressed between layers of soft mud that hardens.It squeezes away the decayed organism leaving only an imprint.

#6 Trace FossilMud or sand hardens into stone where a footprint, trail, or burrow of an organism was left behind.

Example: TrilobiteRanged in size from 1-3 inches to 2-3 feet.Existed for almost 300 million years.Went extinct about 250 million years ago.Related to todays horseshoe crabs.