Transcript Dinosaurs - Fact and Fiction

Bell work
 Grab a book from the shelf and complete pg
122-123 # 1,2,6,7,8 just write the answers!!
The Fossil Record
Chapters 4-5
Fossils
Fossils are the trace remains of an
organism that lived long ago, most
commonly preserved in sedimentary
rock.
Fossils- Trace Fossils
A trace fossil is any evidence of animal
activity. (Ex. Tracks, Burrows,
coporolite)
Burrows are shelters animals bury
themselves in
Burrows
Fossils-Molds
A fossil mold is a cavity in a rock in
which a plant or animal was buried.
Fossils-Cast
A fossil cast is created when sediment
fills a fossil mold and becomes rock.
Index Fossil
An index fossil is a fossil that is used to
establish the age of a rock layer because
the fossil is distinct, abundant, and
widespread and the species that formed
that fossil existed for only a short span of
geologic time.
The Fossil Record
The fossil record is
a historical
sequence of life
indicated by
fossils found in
layers of Earths’
crust.
Relative Dating
Relative dating is any
method of
determining
whether an event or
object is older or
younger than other
events or objects.
Example of Relative Dating
Relative Age
Relative age is the
approximate age of
fossils or other objects
in rock layers
determined by
comparing whether
the surrounding rock
layers are younger or
older.
Geological Column
The geological column
is an ordered
arrangement of rock
layers that is based
on the relative ages
of the rocks and in
which the oldest
rocks are at the
bottom.
Absolute Dating
Absolute dating is any method of
measuring the age of an event or object
in years.
Half-life: time it takes for half of unstable
atoms in a sample to decay.
Using Fossils to Date Rocks
Scientists
have found that
particular types of fossils
appear only in certain layers
of rock.
• By dating rock layers above and
below these fossils, scientists
can determine the time span in
which the organism lived.
• If the organism lived for a
relatively short period of time,
its fossils would show up in
limited layers.
Geologic Time Scale
The geologic time
scale is the
standard method
used to divide
Earth’s long
natural history
into manageable
parts.
Divisions of Geologic Time
Eon- the largest division of geologic time.
Era- a unit of geologic time that includes
two or more periods.
Period – a unit of geologic time that is
longer than an epoch but shorter than an
era.
Epoch- A subdivision of geologic time that
is longer than an age but shorter than a
period.
The Principle of
Uniformitarianism
Uniformitarianism is a principle that
geologic processes that occurred in
the past can be explained by current
geological processes.
Catastrophism
Catastrophism is a principle that states
that geologic change occurs suddenly.