Fossils
True or False: Fossils can be used to give geologists hints about what the past environment was when that animal lived and a general time frame that rock layer was laid down in.
TRUE
The age of a rock layer compared with the age of another rock layer is an example of
The relative age of rock layers
What organism was the first to live on Earth?
Single celled organisms such as Bacteria
What is the longest of the 4 ways time is measured on a geologic time scale?
Eons
What are the shortest of the 4 ways time is measured on a geologic time scale?
Epochs
What are fossils?
Pieces or remains of dead animals
What does the Law of Superposition state?
The oldest rocks are on the bottom, the youngest on the top as long as the layers are undisturbed
This event, likely caused by a large asteroid, caused the extinction of the dinosaurs and ended what ERA?
Mesozoic Era
What are the Eons before our current Eon called?
Hadean and Archean
What organisms were dominant during the "Era of Reptiles" known as the Mesozoic ERA?
Dinosaurs
A fossil of a tropical plant that is found under a SHEET of THICK ICE indicates that the land must have _____ over many years to be where it is now.
MOVED! Theory of Plate Tectonics states the land masses are in constant slow motion!
What is the difference between absolute and relative dating?
Absolute dating gives a year or range of years that something lived in. (It's more specific).
Relative dating gives a sequence of time, what comes first, then next. (General)
What type of animal became abundant after the extinction of dinosaurs?
mammals
The epochs, periods, eras, and eons are an examples of (?) intervals. They are a way to measures the long history of the Earth in what way, they are amounts of what?
Time Intervals
How do you make fossil dating more accurate?
Use absolute or radiometric dating (and combine with other methods).
True or False: In an undisturbed rock layer sequence, the youngest rocks are usually found on the top.
TRUE
When melted rock cuts through older rock layers and then cools, it forms this type of feature, which is younger than the layers it cuts across.
Intrusion
What is the era we live in?
Cenozoic
What would cause a period to change?
Different Weather/Ice Age
Different Continents
New Species
What is an index fossil?
A fossil of an organism that only existed for a short period of time.
Layers of visually distinguishable rock or soil.
Strata
How old is the Earth?
4.6 billion years old
What causes Eras to change?
A mass extinction event
From largest to smallest, this is the correct order of the main divisions of the geologic time scale.
Eon, Era, Period, and Epoch