Download - Geologic time scale
Geologic Time Scale (pg 6)
Geologic Time Scale (pg 6)
• A timeline of Earth’s history
Geologic Time Scale (pg 6)
• A timeline of Earth’s history• Based on both relative dating and absolute
dating
Geologic Time Scale (pg 6)
• A timeline of Earth’s history• Based on both relative dating and absolute
dating• Divides time into eons, eras, and periods
Creating the Geologic Time Scale
• The divisions are based on changes in the fossil record in different layers of rock
Creating the Geologic Time Scale
• The divisions are based on changes in the fossil record in different layers of rock
• Scientists use radiometric dating to determine the age of each rock layer
Eras1. Precambrian: Covers almost 90% of Earth’s
history. Single-celled organisms
Eras1. Precambrian: Covers almost 90% of Earth’s
history. Single-celled organisms2. Paleozoic: Animals and plants appear. This
era begins with the “Cambrian explosion” with many strange new types of animals
Eras1. Precambrian: Covers almost 90% of Earth’s
history. Single-celled organisms2. Paleozoic: Animals and plants appear. This
era begins with the “Cambrian explosion” with many strange new types of animals
3. Mesozoic: Dinosaurs, mammals, and flowering plants appear
Eras1. Precambrian: Covers almost 90% of Earth’s
history. Single-celled organisms2. Paleozoic: Animals and plants appear. This
era begins with the “Cambrian explosion” with many strange new types of animals
3. Mesozoic: Dinosaurs, mammals, and flowering plants appear
4. Cenozoic: Mammals become dominant