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.