Dating Stuff
What is the principle that states each layer of rock is younger than the layer below it?
The Law of Superposition
What is the age of Earth?
4.6 Billion
What is the term for a species that has completely died out?
Extinct
What event brought an end to the Mesozoic Era and killed the dinosaurs?
Meteor impact & volcanic eruptions
Comparing the age of something to the age of something else
Relative dating
When did Pangaea break up?
220 Million Years ago
Name a substance that can preserve an organism for the future
Mud, Sediment, Ice, Amber, Tar
What are the largest units of geologic time called?
Eons
The time it takes for half of the radioactive atoms in a substance to decay into something else.
Half-Life
This type of fossil is tremendously useful for finding the absolute age of a rock layer
Index fossil
Term for when many species of organisms die off all at once.
Mass Extinction
What are the smallest units of geologic time called?
Epochs
Term for the exact age of something
Absolute age
Term for an igneous rock that has forced it's way into sedimentary layers after they have been settled in.
Intrusion
When did the first single-celled organisms appear on Earth?
The Precambrian
What is the name of the long span of time that begins the geologic time scale?
Precambrian
This method of finding absolute age involves comparing the amount of decayed substance to the amount of remaining substance in the rock.
Radioactive Dating
Weathering & erosion or fault activity can lead to this, which breaks the Law of Superposition
An unconformity
What is the term for a species that remains living today?
Extant
What is the age of the universe?
13-14 Billion Years