Recognizing and Preserving Fossils

Recognizing Fossils: How can fossils often be recognized?

They may resemble modern organisms

Recognizing Fossils: What happens when fossils are older?

The farther back in time, the less they resemble modern life

Recognizing Fossils: How are trilobites and pill bugs similar?

They look similar in body shape but are not the same species

Recognizing Fossils: Where did trilobites live comapred to pill bugs?

Trilobites live in oceans while pill bugs live on land

Recognizing Fossils: Why are trilobites important?

They were among the first animals with hard shells

Recognizing Fossils: What geologic period are trilobites from?

Cambrian Period

Recognizing Fossils: Why are fossil ferns significant?

They were among the earliest land plants in the fossil record

Recognizing Fossils: How were ancient ferns different from modern ferns?

Ancient ferns develop trunks and grew tall
like trees now; modern ferns are small understory plants

Fossil Preservation: What is an original shell fossil?

Hard parts preserved with little modification

Fossil Preservation: What is a mold fossil?

An imprint left in sediment after the organism decays

Fossil Preservation: What is a cast fossil?

A mineral-filled copy formed when a mold is filled and hardens

Fossil Preservation: Easy way to remember mold vs cast?

Mold = imprint; Cast = filled-in copy

Fossil Preservation: What is carbon replacement?

Original hard parts replaced by carbon in oxygen-poor environments, such as swamps; leaves a thin film of carbon instead of the original organic matter

Fossil Preservation: What is amber preservation?

An organism trapped in tree sap that hardens into amber