The Precambrian Earth to the present.

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The Precambrian Earth to the present.

• 4.5 Billions years in 2 weeks!

PowerPoint Notes created by S. Koziol Date
12/30/2013 Revised ?/?/??
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Objectives Slides 2-21

• Describe the formations of Earths atmosphere and
  oceans.
• Identify the origins of oxygen in the atmosphere.
• Explain the evidence that oxygen existed in the
  atmosphere during the Proterozoic.
• Describe the experimental evidence of how life
  developed on Earth.
• Distinguish between prokaryotes and eukaryotes.
• Identify when the first multicellular animals
  appeared in geological time.

• Describe the evidence used to determine the age
  of the Earth
• Understand why scientist theorize that the early
  Earth was hot.
• Explain the origins of Earth Crust.
• Describe the formation of the Archean and
  Proterozoic continents.

3
Earth our Solar System

• Most astronomers agree that the solar system,
  including Earth, formed all at once, and
  therefore Earth and meteorites should be about
  the same age.

4
Earths Crust

• Earths earliest crust likely formed as a result
  of the cooling of the uppermost mantle.

5
Oldest Mineral

• The oldest known mineral on Earth is zircon.

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Laurentia (North American Craton)

• Ancient continent that contained core of
  modern-day North America

7
Precambrian shield

• Continental core of Archean and Proterozoic rock.
  aka Canadian shield - The Precambrian shield in
  N.A.

8
Craton

• is an old and stable core of the continental
  crust - the buried and exposed parts of a
  continental shield together compose it.

9
Precambrian shield vs. Canadian shield

• A Precambrian shield is a continental core of
  Archean and Proterozoic rock

• The Canadian Shield is the Precambrian shield of
  North America.

10
Orogens

• Orogens are seams where microcontinents were
  joined together. These seams are belts of
  deformed rocks that form mountain ranges.

11
Ozone O2

• The ozone layer that filters ultraviolet
  radiation originated from oxygen produced by
  stromatolites.

12
Outgassing

• The process by which volcanoes vent water vapor,
  carbon dioxide, nitrogen, and other substances is
  called outgassing.

13
Photosynthesis

• Cyanobacteria use the process of photosynthesis
  to produce energy, and oxygen is given off as a
  waste product.

14
Banded iron formation

• These are deposits consisting of alternating
  bands of chert and iron oxide.

15
Red beds

• Sedimentary rocks younger than 1.8 billion years
  that are colored by the iron oxides in them.

16
Start of life

• Amino acids have been found in the waters of
  hydrothermal vents, suggesting that proteins and
  nucleic acids could have formed there during the
  Archean.

17
Miller and Urey

• Miller and Urey demonstrated that the basic
  building blocks of life were most likely present
  on Earth during the Archean.

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Miller and Urey (continued)

• Heat, cyanide, and certain clay minerals can
  cause amino acids to join together in chains.

19
Prokaryote.

• An organism composed of a single cell that does
  not contain a nucleus and is the simplest kind of
  cell is a prokaryote. Prokaryotes belong to the
  Kingdom Monera.

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Prokaryote vs. Eukaryote

• A prokaryote is a simple organism composed of a
  single cell, which does not contain a nucleus.

• A eukaryote is an organism that is composed of
  multiple cells, which contain nuclei and are more
  complex and larger than those of prokaryotes.

21
Extinctions

• A major extinction of acritarchs occurred near
  the end of the Proterozoic, in which widespread
  glaciations may have played a critical role.

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Objectives Slides 23-38

• Describe the paleogeography of Laurentia.
• Discuss the concept of a passive margin.
• Describe the Cambrian fauna.
• Describe the Middle Paleozoic paleogeography.
• Explain the concept of an active margin and the
  formation of a clastic wedge.

• Describe the Middle Paleozoic fauna.
• Define the concept of mass extinction.
• Describe the formation of Pangaea.
• Explain how cyclotherms formed.
• Identify the importance of amniote eggs.
• Discuss the causes of the Late Permian mass
  extinction.

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Paleogeography

• Ancient geographic setting of an area.

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Laurentia

• During the Cambrian, Laurentia was covered by a
  sea.

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Laurentia - Precambrian

• On Laurentia, large, sandy beaches formed when
  sand-sized fragments of quartz were weathered
  from the rocks of the Precambrian Shield and
  transported to the shoreline.

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Passive Margin

• When there is no tectonic activity along the edge
  of a continent, the edge is referred to as a
  passive margin.

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Cambrian explosion

• During the Cambrian explosion, all but one of the
  major marine phyla appeared.

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Cambrian explosion (continued)

• The Cambrian explosion was marked by great
  diversity of life, including the development of
  animals with skeletons.

29
Burgess Shale

• Burgess Shale - Contains fossils of soft-bodied
  Cambrian organisms

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Evidence of past lagoons

• Fragile organisms can live in a lagoon, which is
  the calm area behind a reef.

31
Reefs

• An organic reef is a structure composed of
  carbonate skeletons made by living organisms,
  such as coral.

32
Taconic Orogeny

• Taconic Orogeny - Mountain-building event named
  for the mountains of eastern New York State

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Clastic Wedge Origins

• A triangular-shaped deposit composed of sediment
  eroded from adjacent mountains is called a
  clastic wedge.

34
The following provides evidence of the Taconic
Orogeny

• angular unconformities
• clastic wedges
• igneous intrusions

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Vascular Plants

• The ability to transfer water through stems and
  stalks characterizes vascular plants.

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Ancestral Rockies

• Mountain range in present-day Colorado formed by
  inland uplift.

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Mountain Building

• The Late Paleozoic was a time of active mountain
  building.

38
Cyclothems

• The series of transgressions and regressions that
  produce cyclothems were likely produced by
  glaciations.

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Objectives Slides 40-59

• Explain the breakup of Pangaea.
• Distinguish between the different characteristics
  of Mesozoic Orogenies.
• Describe how paleontologists distinguish among
  reptile, dinosaur and mammal fossils.
• Describe the type of tectonism that characterized
  the Cenozoic orogeny.

• Understand the extent of glaciation that occurred
  in N.A..
• Discuss the changes in animals in N.A. during the
  Cenozoic.
• Identify the characteristics of primates.
• Explain what separates hominids from the other
  hominoids.

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200 MYA

• As North America rifted from Europe and Africa, a
  continuous rift system called the Mid-Atlantic
  ridge was formed.

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New Oceans

• As Pangaea split apart, the rifts flooded to form
  new oceans.

42
Pangaea break-up

• Pangaea probably broke apart because it held heat
  beneath it, which caused the continent to expand
  and then fracture and break apart.

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Mesozoic orogenies

• As a result of the earliest of the Mesozoic
  orogenies in North America, large bodies of
  granite called batholiths exist throughout the
  Cordillera.

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Mesozoic orogenies (continued)

• Orogenic events at the end of the Mesozoic
  uplifted massive blocks of crust to form the
  Rocky Mountains.

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First Angiosperms

• Angiosperms - Seed-bearing plants that have
  flowers

Archaefructaceae
46
Phytoplankton

• Tiny, ocean-dwelling organisms called
  phytoplankton made up the base of the food chain
  during the Mesozoic.

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Vertebrates and Invertebrates from among the
modern fauna.

• Vertebrates bony fishes, sharks, aquatic
  reptiles, and aquatic mammals

• Invertebrates crabs, lobsters, shrimps, sponges,
  sea urchins, modern corals, snails, and clams.

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Mesozoic ammonites

• Fossils of ammonites are often used as index
  fossils because these marine animals were
  widespread and abundant during the Mesozoic.

49
Early Mammals

• Early mammals with a single jawbone arose from
  mammal-like reptiles.

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Sauropod

• The largest land animals that ever lived were the
  quadrupedal, plant-eating sauropods.

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S.W. U.S. tectonism

• The subduction of the East Pacific Rise coincides
  with pull-apart tectonism in the southwestern
  United States.

52
Pliocene ice age

• As the Pliocene ice age began, great savannas
  became arid land and many savanna mammals became
  extinct.

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Pliocene ice age (continued)

• The change of climate caused many of the savanna
  mammals to become extinct. New animals came to
  populate the land, including sabre-toothed cats,
  mammoths, giant vultures, giant ground sloths,
  and huge wolves.

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Pliocene ice age (continued)

• During the Pliocene, the water of the Arctic
  Ocean began to freeze to form an arctic ice cap.
  Glaciers from the arctic advanced and retreated
  in at least four stages over North America.
  Glaciers extended as far south as the present-day
  Ohio and Missouri Rivers.

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Pliocene ice age (continued)

• The southernmost point to which glaciers advanced
  in North America is marked by the paths of the
  Ohio River and the Missouri River.

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Eocene Mammals

• Most of the currently living groups of mammals
  had appeared by the Eocene.

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Primate Traits

• Primates - Mammal possessing specialized traits
  related to arboreal lifestyle

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Primate Traits (continued)

• Two important anatomical traits of all primates
  are an opposable thumb and forward-facing
  eyes.

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Us (you I)

• Homo sapiens - Modern human species