GEOLOGIC TIME SCALE AND FOSSILS OUTLINE
I.
Precambrian – Earliest span of time in Earth’s history. Covers ______% of Earth’s
4.6 billion years.
II.
3 Major Eras
a. Paleozoic – (lasted 300 million years) first period is the Cambrian Period, also
known as the age of the Trilobites. Brachiopods, fish, first amphibians.
- Early land plants – Ferns, mosses, and Cone-bearing plants
b. Mesozoic Era - Age of the Dinosaurs. (lasted 180 million years) ended 65 millions
years ago with a mass extinction.
Triassic Period – Small Reptiles
Jurassic Period – Larger Reptiles
Cretaceous Period – Small mammals and birds
c. Cenozoic Era – Age of the Mammals
Quaternary Period – Holocene Epoch – Ice Ages
Cats, dogs, bats, whales, dolphins, and Humans.
Present day
II.
Era Divisions
a. First Mass Extinction between Paleozoic and Mesozoic Era – 90% ________ life
and 70% ______ animals became extinct.
b. Second Mass Extinction between Mesozoic Era and Cenozoic Era – Caused by
comet or asteroid. Dinosaurs wiped out.
c. Smaller divisions such as Periods and Epochs are placed because of changes in
the animals and plant life.
III.
Cause and Effect
a. continental drift caused changes in climates - Pangaea
b. changes in oceans
c. changes in development of mountains caused climate changes
d. volcanic eruptions caused climate changes (convergent boundaries)
e. asteroids and comets caused climates changes
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I.
Fossils are formed
a. Clues to Diversity of Living Things.
II.
Different Types of Fossils based on How Formed.
a. Mold Fossil
b. Cast Fossil
c. Petrified Fossil
d. Preserved Fossil
e. Carbonized Fossil
f. Trace Fossil
III.
Examples of Fossils.
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Relative and Absolute Ages of rocks:
Relative Age: The _______ of a rock _______________ to the ages of rock _________.
Absolute Age: The ______ of a rock given as the _______________ of years since the
__________ formed.
_____________________________ : in horizontal sedimentary rock layers, the __________
layer is at the __________. Each higher layers is ______________ than the layers below it.
OTHER CLUES TO RELATIVE AGE!!
A. IGNEOUS ROCKS (2 TYPES)
1. INTRUSION:
2. EXTRUSION:
B. FAULTS
UNCONFORMITY is a _______ in the _______________ record. An unconformity show
where some _____________ layers have been _____________ because of erosion.
INDEX FOSSIL: Fossils of ___________ distributed organisms that lived during only a
short period of time. Example - TRILOBITE