October 27,2011
ObjectiveTo learn how the
geologic timeline was made and how the length of the various periods are different
AgendaProgress reports –
need to be signed by Parent/guardian
Geologic History Notes
Project –highlightsLab: Geologic
Timeline
Structure of the Time Scale
The Geologic Time Scale
Based on their interpretations of the rock record, geologists have divided Earth’s 4.56-billion-year history into units that represent specific amounts of time. Taken together, these time spans make up the geologic time scale.
Structure of the Time Scale
12.4 The Geologic Time Scale
Eons represent the greatest expanses of time. Eons are divided into eras. Each era is subdivided into periods. Finally, periods are divided into smaller units called epochs. There are three eras within the Phanerozoic eon: the Paleozoic, which means “ancient life,” the Mesozoic, which means “middle life,” and the Cenozoic, which means “recent life.”
The Geologic Time Scale
Precambrian Era
The Precambrian era lasted from Earth’s formation 4570 until 542 million years ago (mya).
The first cells appeared in the Precambrian era.
Paleozoic Era
The Paleozoic era lasted from 542 to 251 mya.
Paleozoic is a Greek word meaning “ancient life.”
Paleozoic Era
Rocks from the Paleozoic Era contain fossils of snails, clams, corals, and trilobites.
Paleozoic Era
Animals with backbones began to appear.
At the end of this era, the continents that existed during this time period collided to form a new supercontinent, Pangaea.
Mesozoic Era
The Mesozoic era lasted from 251 to 65 mya. This era is often called the Age of Reptiles.
Cenozoic EraThe Cenozoic era began 65 mya and is
still going on. The common name for the Cenozoic Era
is the Age of Mammals.
Cenozoic Era
Mammals diversified into a variety of species including land mammals, sea mammals, and flying mammals.
Cenozoic means “recent life.”
Mastadon Stromatolites Apatosaurus
(Brontosaurus) Orthoceras Nautiloid Eurypterids Trilobites Velociraptor Chesapecten jeffersonius
( State Fossil) Carcharodon Megalodon Spinosaurus Cave Bear (Ursus
speleaus) Ichthyodectes ctenodon Coelophysis Quagga Giganotosaur
Ohmdenosaurus Zephyrosaur Wuerhosaurus Torosaurus latus Elasmosaurus platyurus Manny: woolly mammoth Sid: ground sloth
(Megalonyx) Diego: saber-toothed
tiger (Smilodon) Scrat: saber-toothed
squirrel (Leptictidium) Dab: dodo Carl: Embolotherium Frank: Brontotherium