Fossil Types
The preserved remains or traces of living things
What is a fossil?
The time period between the Pre -Cambrian and present time period; Paleozoic, Mesozoic and Cenozoic
What are eras?
Scientists that study fossils
What is a paleontologist?
A hollow area in sediment in the shape of an organism or part of an organism
What is a mold?
Provides evidence of the activities of ancient organisms
What is a trace fossil?
Eras that are subdivided. Many of the names come from places where fossils were discovered
What are periods?
To determine the relative age of a rock. It states that in undisturbed horizontal sedimentary rock layers the oldest is at the bottom Each higher layer is younger than the one below it.
What is the Law of superposition?
A solid copy of the shape of an organism
What is a cast?
A fossil that is widely distributed and and in existence for a relatively short period in geologic history. They are useful because they tell tell the relative age of the rock in which they are found.
What is an index fossil?
The number of years that have passed since a rock formed.
What is absolute age?
Elements that release particles of energy and they break down or decay over time. Atoms of one element break down to form atoms of another element.
What is Radioactive Decay?
An extremely thin coating of carbon on rock - a fossil type
What is carbon film?
Fossils in which minerals replace all of an organism or part of an organism such as a dinosaur bone
What is a petrified fossil?
The age of a rock compared to other rocks, i.e. older or younger than
What is relative age?
When an organism no longer exists and will never again on earth
A process that preserves entire organisms, i.e. tar, tree resin, freezing
What are preserved remains?
It is the time it takes for a radioactive element for half of the elements to decay
What is half-life?
The key principle that guides scientists when they make inferences about Earth's past and is states that the geologic processed that operate today also operated in the past
What is Uniformitarianism?