FOSSILS UNIT ONE

How do most fossils form? WARM-UP #1 How do most fossils form?

Living things die and their remains are covered by sediments. ANSWER Living things die and their remains are covered by sediments.

WARM-UP #2 A fossil formed when minerals replace all or part of an organism is called____________.

ANSWER Petrified fossil

WARM-UP #3 Which type of fossil can provide clues about the activities of ancient organisms?

ANSWER Trace fossil

VOCABUALRY Fossil Mold & cast Petrified

VOCABULARY Fossil A trace of an ancient organism that has been preserved in rock Mold & cast A fossil formed when an organism buried in sediment dissolves, leaving a hollow area

A fossil in which minerals replace all or part of an organism VOCABULARY Petrified A fossil in which minerals replace all or part of an organism

WARM-UP #4 The fossil record shows that life on Earth has changed over time. For example, paleontologists have found that older rocks contain fossils of

organisms that are simpler than those alive today. ANSWER organisms that are simpler than those alive today.

The relative age of a rock is WARM-UP #5 The relative age of a rock is

its age compared to the ages of other rocks. ANSWER its age compared to the ages of other rocks.

WARM-UP #6 The law of superposition states that, in horizontal layers of sedimentary rock, each layer is

older than the layer above it and younger than the layer below it. ANSWER older than the layer above it and younger than the layer below it.

VOCABUALRY Carbon film Trace Paleontologist

VOCABUALRY Carbon film A type of fossil consisting of an extremely thin coating of carbon on rock Trace A type of fossil that provides evidence 0f the activities of the ancient organism

VOCABUALRY Paleontologist A scientist that studies fossils to learn about organisms that lived a long time ago

WARM-UP #7 What is the age of an intrusion of igneous rock in relation to the sedimentary rock layers through which it passes?

ANSWER always younger

WARM-UP #8 The fossils of organisms that were widely distributed but only lived during a short period of time are called

ANSWER index fossils.

Why are index fossils useful to geologists? WARM-UP #9 Why are index fossils useful to geologists?

They tell the relative age of the rock in which they occur. ANSWER They tell the relative age of the rock in which they occur.

VOCABUALRY Relative age Absolute age Law of superposition

VOCABUALRY Relative age The age of a rock compared to the ages of rock layers Absolute age The age of a rock given as the number of years since the rock formed

VOCABULARY Law of superposition The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it

The earliest life forms were WARM-UP #10 The earliest life forms were

single-celled organisms. ANSWER single-celled organisms.

WARM-UP #11 What is a fossil?

the preserved remains or traces of an organism ANSWER the preserved remains or traces of an organism

WARM-UP #12 In which type of fossil might you find the remains of an insect preserved with little or no change?

ANSWER fossil in amber

VOCABUALRY unconformity Index fossil

VOCABUALRY Unconformity A place where old, eroded rock surface is in contact with a newer rock layer Index fossil Fossils distributed organisms that lived during only one short period

WARM-UP #13 A type of organism that no longer exists on Earth is said to be __________.

ANSWER extinct.

Fossils usually occur in _____________________ rock. WARM-UP #14 Fossils usually occur in _____________________ rock.

ANSWER sedimentary

Generally, only the ________ parts of organisms become fossils. WARM-UP #15 Generally, only the ________ parts of organisms become fossils.

ANSWER hard

VOCABUALRY Hydrocarbon Petroleum

VOCABUALRY Hydrocarbon An energy-rich chemical compound that contains carbon and hydrogen atoms petroleum Liquid fossil fuel; oil

Footprints and trails are examples of__________________. WARM-UP #16 Footprints and trails are examples of__________________.

ANSWER Trace fossils

WARM-UP #17 The law of superposition helps geologists determine the________________ age of a rock layer.

ANSWER relative

WARM-UP #18 Rock layers are always _______________ than the faults that cut across them.

ANSWER older

VOCABUALRY