TuesdayNovember 27,

2012(The Phanerozoic

Eon:The Paleozoic Era -

Life Explodes)

The Launch PadTuesday, 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 PadTuesday, 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

Announcements

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Cat Day

Assignment Currently Open

Summative or

Formative?Date Issued Date Due Date Into

GradeSpeed Final Day

Quiz 11 S1 11/9 11/9 11/30Lab – The

Geologic Time Scale

F3 11/14 11/16 11/30

Quiz 12 S2 11/16 11/16 12/7WS - The

Precambrian Eon: Formation of

Continents and Steps Leading to Higher Life Forms

F4 11/26 11/30 11/30

Recent Events in ScienceNearby Rogue Planet Found

Astronomers using ESO’s Very Large Telescope and the Canada-

France-Hawaii Telescope have identified a body that is very probably a planet wandering

through space without a parent star. This is the most exciting free-

floating planet candidate so far and the closest such object to the Solar System at a distance of about 100

light-years. Its comparative proximity, and the absence of a bright star very close to it, has allowed the team to study its

atmosphere in great detail. This object also gives astronomers a

preview of the exoplanets that future instruments aim to image around

stars other than the Sun.

Read All About It!www.eso.org/public/news/eso1245/

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 Invertebrate

s.”

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 ExplodesThe 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.

TrilobitesCephalopods

SpongesCorals

The Paleozoic Era: Life ExplodesDuring 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 ExplodesA 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