Extinct: When an animal is extinct it is not existing
mass extinction: Widespread and rapid loss of biodiversity
Precambrian Era
● Age of early life
● Longest era
● Lasted for over 90% of the earth
● Hadean Time and the Phanerozoic Eon
Mesozoic era:
It is the age of the dinosaurs. It was between 230 and 65 years ago.
Reptiles are the dominant
Cenozoic era: it is the era of mammals, 65 million years ago to the present.
Criteria: The requirement(s) or standard that needs to be met; prerequisite
Index fossil: Fossils that are used for dating and finding geologic time
periods
Biodiversity: The variety of life in an ecosystem
Sedimentary rock: The collection of minerals or organic matter that settles
on Earth’s surface
Metamorphic rock: Forms in high heat and pressure circumstances
Raptors:
Lived 75 - 71 million years ago
First discovered in the Gobi Desert, Mongolia on August 11, 1923
How do we know the age of this fossil? This is the place you describe the
difference between relative dating and radioactive dating.
Scientists can