Fossils are found most often in which type of rock?
Sedimentary
100
In an undisturbed rock layer, where do you find the oldest layer?
At the bottom
100
How old is the Earth?
4.6 billion years
100
Geologic time scale shows Earth's _____________
history
200
Define trace fossil. Give 3 examples
A fossil that shows the activities of an organism.
Burrow or nest, animal track or animal footprint, waste
200
What is a break or crack in a rock layer?
A Fault
200
A radioactive sample of 1000 grams has a half life of 2,000 years. How much will be left after 1 half life?
500 grams
200
What is the largest division of geologic time?
Eon
300
What type of organism parts are more likely to become a fossil?
Hard parts - like bone and marine organisms over land organisms
300
In an undisturbed rock sequence, where would the youngest layer be located?
At the top
300
A radioactive sample of 1,000 grams has a half life of 2,000 years. How much will be left after 6,000 years?
125 grams
300
What is the smallest division of geologic time?
Epoch
400
What has to happen for an organism to become a fossil?
It has to be covered or buried by sediments
400
Which is younger, the top layer or an intrusion that reaches the top layer?
The intrusion
400
Absolute dating give an actual __________ __________ like your age
number value
400
What organism did not live during the age of the dinosaurs?
Mammals like humans
500
Organisms can be preserved in ice, amber, and volcanic ash. True/False
Name a place that has ice and a place with volcanic ash
True
Siberia and Italy
500
How do you determine the relative age of a rock layer?
by looking at the position of the layer and comparing it to other layers
500
To determine the absolute date of an object you must compare one layer to another layer?? True/False
How do you determine the absolute age of an object?
False
500
List the divisions of geologic time in order from largest to smallest.