Types
of
Fossils
of
Fossils
forms when minerals soak in buried remains, replacing them into rock form
Petrified/ Permineralized Fossil
How many eras are there
4
What is the Law of Superposition?
Each rock layers is older than the one above it
There was a rise of Simple’s organisms so it began with Simple life forms.(1st era of time)
Precambrian Era
The exact era or century of time, in a certain/specific time period.
Absolute Age
Forms when entire organisms or part of organisms are prevented from decaying by being trapping in rock, ice, tar, or amber.
Preserved Fossil
When did the first insect fossils get discovered?
440 million years ago
The very bottom layer that has no same type of rock as the layers above.
The oldest layer.
Reptiles were dominant species of this era, small mammals and birds also appeared. at the end of this era caused their dinosaurs to become extinct.
Mesozoic Era
Doesn’t tell exact age, can be found by ordering rock layers and index layers.
Relative Age
Forms when a mold is filled with sand or mud that’s hardens into the shape of the organisms.
Cast Fossil
When did there earth begin?
4.5 billion years ago
What type of dating do we use to measure rocks age?
Relative age and Absolute age
The current era, the diversity of life forms increased, and humans are also part of this era.
Cenozoic Era
Special types of atoms that “fall apart“ on predictable time schedules.
Radioactive Isotopes
The remains of animals that existed for a relatively short period of geological history.
Index fossil
When did the vertebrae fossils begin?
417 million years ago
What order does age go as in the layers of rock
Oldest on bottom and gets younger as it goes up
A distinct period of geological time/s
Eras
Geological time
What fossil forms when the mud or sand hardens to stone where a organisms print was left behind.
Trace Fossil
When did eukaryotic cells begin?
1.8 billion years ago
What is Relative Measurments?
When age is determined by the relative order in which they appear.
Ended in a mass extinction, reptiles were dominant species at the end of this era.
Paleozoic era
Refers to all fossils that have been found since the study of fossils began
Fossil Record