The Precambrian Earth to the present.

1. The Precambrian Earth to the present. 4.5 Billions years in 2 weeks! PowerPoint Notes created by S. Koziol Date : 12/30/2013 Revised : ?/?/??

2. Objectives Slides 2-21 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. Describe the formations of Earth’s 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.

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. Earth’s Crust Earth’s 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.

6. 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.

18. 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.

20. Prokaryote vs.Eukaryote A eukaryote is an organism that is composed of multiple cells, which contain nuclei and are more complex and larger than those of prokaryotes. A prokaryote is a simple organism composed of a single cell, which does not contain a nucleus.

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

22. ObjectivesSlides 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.

23. Paleogeography Ancient geographic setting of an area.

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

25. 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.

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

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

28. 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

30. 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

33. 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

35. Vascular Plants The ability to transfer water through stems and stalks characterizes vascular plants.

36. Ancestral Rockies Mountain range in present-day Colorado formed by inland uplift.

37. 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.

39. ObjectivesSlides 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.

40. 200 MYA As North America rifted from Europe and Africa, a continuous rift system called the Mid-Atlantic ridge was formed.

41. 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.

43. 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.

44. Mesozoic orogenies (continued) Orogenic events at the end of the Mesozoic uplifted massive blocks of crust to form the Rocky Mountains.

45. 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.

47. 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.

48. 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.

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