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
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.”
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.”
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.