Fossils
What is a fossil?
Remains of ancient organisms that are preserved.
What is a rock layer?
A distinct layer of rock
What does the geologic time scale show?
Earth's history divided into time periods.
What is a widespread and rapid decline in global biodiversity where at least 75% of Earth's species vanish within a geologically short period of time?
Mass extinction
Explain the concept of relative age.
It shows us what layers of rock are older and what layers of rock are younger.
What is an index fossil?
A fossil that lived for a short time period, and in a lot of different places. It gives us a marker for a certain time period
What is the principle of superposition?
Oldest layers are at the bottom.
Name one era on the geologic time scale.
Paleozoic, Mesozoic, or Cenozoic.
How many mass extinctions have there been?
5
How do geologists determine the age of rock layers?
By using absolute (radiometric) and relative dating
Name one type of fossil.
Petrification (Replacement & Permineralization), Molds and Casts, Carbonization, Fossil Resin (amber), Tar and Ice, Trace Fossils,
What can you learn from rock layers?
They show Earth's history and past life.
What is the difference between an era and a period?
An era contains multiple periods.
What might be causing the 6th mass extinction?
Human activity
What element do we often use for the radiometric dating of fossils?
Carbon-14
How do fossils form?
They form when organisms are buried quickly.
What does original horizontality mean?
Layers are originally flat.
How is the geologic time scale divided?
Divided into eons, eras, periods, and epochs.
The most recent extinction is called.
Cretaceous-Tertiary extinction event.
What is the significance of studying rock layers?
They help understand geological events and timelines.
Why are fossils important?
They help us learn about past life and environments.
How do we determine the age of rock layers?
By studying fossils and using dating methods.
Why is the geologic time scale important?
Helps understand Earth's history.
In all the past mass extinction what group of animals made up the majority of those who went extinct?
Marine invertebrates
How can changes in rock layers indicate past environmental conditions?
Changes can show shifts in climate, sea levels, or ecosystems.