Science 2

The calico scallop is an index fossil. It is well documented to have lived 1.8 million years ago. Therefore, the approximate age of the rock in which this fossil is found is

1.8 million years.

How are fish often preserved?

Carbonization

What fossilization process involves the transformation of organic material into a thin film by water?

Carbonization

What forces constantly destroy fossils?

Erosion and Weathering

If the same sequence of rock layers is observed over a large area, ____.

a large deposit of rock formed over a large area

____ dating uses the properties of atoms in rocks and other objects to find their ages.

absolute

With ____ dating, a rock's exact age can be determined, whereas with ____ dating, a rock's age is compared to the ages of other rocks.

absolute, relative

All of the following conditions help preserve organisms as fossils EXCEPT ____.

activities of microorganisms

Fossils up to 75,000 years old can be dated with ______.

carbon-14

fossil formed when an outline of the original organism is formed from left-over carbon

carbonaceous film

made when sediments fill in a cavity made when an object decayed and the sediments harden into rock

cast

Absolute age examines the position of rocks in a sequence.

false

Dinosaur footprints are original remains.

false

Radiocarbon dating would be useful in dating the age of Earth.

false

Scientists are able to determine the relative age of rocks in specific years.

false

The half-life of a material increases with the amount of material present.

false

To be a useful index fossil, a species must have been rare.

false

A ______ may tell a geologist when, where, and how an organism lived.

fossil

Rock layers are correlated if they both contain the same ____.

fossils

Index fossils are the remains of species that were once abundant and .

geographically widespread

the time it takes for half of the atoms in an isotope to decay

half-life

The ______ parts of organisms are most likely to become fossils.

hard

A fossil is a :

hardened remains

fossils of species that lived on Earth for short periods of time and were abundant and were widespread geographically

index fossils

In a series of undisturbed rock layers where shale lies between sandstone below and limestone above, the ____.

limestone is youngest

A ______ is the cavity left behind in the rock after an organism's hard part has dissolved.

mold

A limestone bed containing fossils that are 550 million years old is ____ a bed of sandstone containing fossils that are 400 million years old.

older than

Scientists who study fossils are called ______.

paleontologists

A fossil's age can be found using all of the following methods except:

physical dating

states that for undisturbed rocks, the oldest rocks are on the bottom and the rocks become younger and younger toward the top

principle of supersition

The process of isotopes breaking down and emitting particles, such as alpha or beta, to form a new substance.

radioactive decay

is measured in half-lives

radioactive decay

Determining the order of events and the relative age of rocks by examining the position of rocks in a sequence is called ____.

relative dating

Fossils are the ______, imprints, or traces of once-living organisms preserved in rock.

remains

You are most likely to find a fossil in which of the following?

sedimentary rock.

What are index fossils used to determine?

the age of the surrounding rock layer

Which principle states that, in undisturbed rock layers, the oldest rocks are on the bottom and the youngest rocks are on top?

the principle of superposition

Why are fossils useful?

they provide evidence of living things.

Carbon films are formed when a thin film of carbon is left, forming a silhouette of the original organism.

true

Fossils most often form when a dead organism is buried in sediments.

true

Radioactive materials dating is a technique to find the absolute age of a fossil.

true

The first group of vertebrates to arise was probably the fishes.

true

Gaps in rock layers are called ____.

unconformities

states that Earth processes today are similar to those that took place in the past

uniformitarianism

If the same index fossils are found in two separate rock layers, the two rock layers most likely

were formed at the same time.