1. Chapter 4 Test Review What are fossils? What is a petrified fossil?
The time it takes for half of the radioactive atoms to decay
Used to determine the absolute age of rocks.
The preserved remains or traces of past organisms
An type of organism which no longer exists on earth
A fossil formed when minerals replace all or part of an organism
88% of earths history
Allow scientists to infer the Earth’s age
A thin coating of Carbon left on a rock
Footprints
All continents joined together about 250 million years ago
How geologists divide Earth’s history
When rock layers are turned over completely
When atoms break down to form other atoms
Describe past environments and history of life
Geologic processes that change Earth today also changed Earth in the past
Mold is the outside shell, cast is the solid copy
When an organism becomes trapped in stick tar or resin
Radio active element used to date remains of organisms
A plentiful, short lived fossil used to date rocks
Age related to other rocks and age since the rock was formed
The youngest rocks are on top and the oldest on the bottom
What are fossils?
What is a petrified fossil?
How have fossils helped scientists?
What does extinct mean?
What does half-life mean?
What is radioactive decay?
How does radioactive dating help scientists?
What is uniformitarianism?
What is folding?
How do moon rocks help scientists determine the Earth’s age?
The pre-Cambrian era covers what percent of earth’s history?
What is a carbon film?
What is a trace fossil?
What is the law of superposition?
What is the geologic time scale?
What is Pangaea?
How do we get preserved remains?
What is Carbon-14 used for?
Compare/Contrast molds and casts.
Compare/contrast relative and absolute age of rocks.
What is an index fossil?

2. What are fossils? The preserved remains or traces of past organisms
What is a petrified fossil? A fossil formed when minerals replace all or part of an organism
How have fossils helped scientists? Describe past environments and history of life
What does extinct mean? An type of organism which no longer exists on earth
What does half-life mean? The time it takes for half of the radioactive atoms to decay
What is radioactive decay? When atoms break down to form other atoms
How does radioactive dating help scientists? Used to determine the absolute age of rocks.
What is uniformitarianism? Geologic processes that change Earth today also changed Earth in the past
What is folding? When rock layers are turned over completely
How do moon rocks help scientists determine the Earth’s age? Allow scientists to infer the Earth’s age
The pre-Cambrian era covers what percent of earth’s history? 88% of earths history
What is a carbon film? A thin coating of Carbon left on a rock
What is a trace fossil? Footprints
What is the law of superposition? The youngest rocks are on top and the oldest on the bottom
What is the geologic time scale? How geologists divide Earth’s history
What is Pangaea? All continents joined together about 250 million years ago
How do we get preserved remains? When an organism becomes trapped in stick tar or resin
What is Carbon-14 used for? Radio active element used to date remains of organisms
Compare/Contrast molds and casts. Mold is the outside shell, cast is the solid copy
Compare/contrast relative and absolute age of rocks. Age related to other rocks and age since the rock was formed
What is an index fossil? A plentiful, short lived fossil used to date rocks