Tuesday November 27, 2012 (The Phanerozoic Eon: The Paleozoic Era - Life Explodes)

The Launch Pad Tuesday, 11/27/12 Describe the process by which continents were formed in the Precambrian Eon. 1.Volcanic island arcs and oceanic plateaus rose up in the ancient seas due to the upwelling of magma from the upper mantle. 3.The crustal provinces then accreted into cratons. 4.The cratons then accreted to form the foundations of the modern continents. 2.The action of plate tectonics caused the arcs to accrete into crustal provinces.

The Launch Pad Tuesday, 11/27/12 Once life had began on the Earth, what four major developments added to the chances of higher life forms evolving in the future? photosynthetic organisms multicellular organisms eukaryotic organisms sexual reproduction

Assignment Currently Open Summative or Formative? Date IssuedDate Due Date Into GradeSpeed Final Day Quiz 11S111/9 11/30 Lab – The Geologic Time Scale F311/1411/1611/30 Quiz 12S211/16 12/7 WS - The Precambrian Eon: Formation of Continents and Steps Leading to Higher Life Forms F411/2611/30

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The Phanerozoic Eon The Phanerozoic Eon encompasses 542 million years, and is still the current Eon. The Phanerozoic Eon is divided into the Paleozoic, Mesozoic, and Cenozoic Eras.

The Phanerozoic Eon The Paleozoic Era The Paleozoic Era was dominated by continental collisions as Pangaea began to assemble.

The Phanerozoic Eon The Paleozoic Era At this time the Caledonian, Appalachian, and Ural Mountains were formed.

The Phanerozoic Eon The Paleozoic Era 542 million years ago, when the Eons changed from the Precambrian to the Phanerozoic, the fossil record blooms as life suddenly appeared in abundance. The development of shells and other hard body parts was the reason. This was known as the “Cambrian Explosion”, as the Cambrian Period was the first of the new Eon.

The Phanerozoic Eon The Paleozoic Era The early Paleozoic Era consisted of the Cambrian and Ordovician Periods. This was known as the “Age of Invertebrates.”

Paleozoic Marine Invertebrates Figure 12.26

The Phanerozoic Eon The Paleozoic Era The middle Paleozoic Era consisted of the Silurian and Devonian Periods. This was known as the “Age of Fishes.”

The Phanerozoic Eon The Paleozoic Era The later Paleozoic Era consisted of the Carboniferous Mississippian, Carboniferous Pennsylvanian, and Permian Periods, when most of the swamps that would become petroleum deposits were laid down. This was known as the “Age of Amphibians.”

Figure 12.27

Pennsylvanian-Age Coal Swamp Figure 12.29

Figure 12.28

The Paleozoic Era: Life Explodes The Paleozoic Era marks the first appearance of life-forms with hard parts such as shells. Life in the early Paleozoic was restricted to the seas and consisted of several invertebrate groups including: This development resulted in abundant Paleozoic fossils. Trilobites Cephalopods Sponges Corals

The Paleozoic Era: Life Explodes During the Paleozoic, organisms diversified dramatically. Insects and plants moved onto land. Lobe-finned fishes adapted to land and became the first amphibians. Large tropical swamps in the Pennsylvanian period became the major coal deposits of today.

The Paleozoic Era: Life Explodes A mass extinction at the close of the Paleozoic Era destroyed 70% of all vertebrate species on land and 90% of all marine organisms.

Figure 12.A (left)

Figure 12.A (right)

Worksheet The Phanerozoic Eon: The Paleozoic Era - Life Explodes