Geographic Time 8.E.6A.1Develop and use models to organize Earth’s history (including era, period, and epoch) according to the geologic time scale using evidence from rock layers

Geologic Time Scale Record of the major events and diversity of life forms present in Earth’s history. Goes from the formation of Earth to Present Day The Time Scale is divided into Eras Further divided into Periods Further divided into Epochs Subdivisions are based on large scale events in Earth’s history that are identified in the fossil record and rock layers At the end of each era, a major mass extinction occurred Many organisms died out, although there were other extinctions going on during each period of geologic time

Precambrian and Phanerozoic First name given to the Earliest span of time in Earth’s history 4.6 Billion years – 542 million years ago Phanerozoic divided into 3 Eras Paleozoic- 542 mya - 251 mya Mesozoic- 251 mya to 65.5 mya Cenozoic- 65.5 mya to present

Paleozoic Era First Period is the Cambrian, most animal phyla appear Early invertebrates, Developed early vertebrate fish, arachnids and insects, Later first amphibians near the Era’s end, Reptiles dominant Early land plants Mosses, ferns, later cone-bearing plants

End of Era, seed plants were common Mass extinction that ended era caused most marine invertebrates as well as amphibians to disappear Formation of Pangaea Last Period was the Permian Rapid global warming and cooling happened 95% of Marine species wiped out 70% of land animals were wiped out Organisms could not adjust

Mesozoic Era Reptiles dominant DINOSAURS Present Small mammals and birds appear End of era, flowering plants appeared and Mammals increased Mass extinction that ended era caused dinosaurs to become extinct Break Up of Pangea into several large continents Mesozoic Era

Cenozoic Era New Mammals emerge while other become extinct Diversity of life increased Flowering plants are most common Humans are also part of the most recent period of this era Present day Earth is in this Era Further splitting and moving of continents to their current positions

Periods of the Cenozoic subdivided into further epochs due to complete fossil record available We are in the Quaternary Period (2.588 mya- present) Holocene Epoch 11,700 years ago to present