What events characterize the major periods of geologic time?

1. What events characterize the major periods of geologic time? A Journey through Geologic Time Section 14.1

2. Geologic Time Scale • Evidence shows that Earth formed about 4.6 billion years ago. • Geologists and Paleontologists base their knowledge on: • Earth’s Rocks • Relative Dating • Radiometric Dating • Fossil Record • Organisms appear in some layers and not in others. www.wikipedia.org www.wikipedia.org

3. Earth’s Rocks • All sedimentary rock is composed of layers. • Sediments from rivers and oceans settle in different locations. • Silt and other components form a cement which hardens into rock.

4. Earth’s Rocks = Species A = Species B = Species C • Relative Dating • Rocks are formed in horizontal layers. • The oldest rocks are found in the deeper layers. • Fossils found in deeper layers were alive much earlier. 65 mya 144 mya 206 mya 243 mya 290 mya

5. Earth’s Rocks = Uranium 235 = Lead 207 • Radiometric Dating • All organisms take in small amounts of radioactive isotopes. • Radioactive isotopes decay at a steady, measurable amount. • A fossil’s date can be determined by the amount of radioactive isotopes and other elements. Time Zero (Rock is Formed) First Half-Life (704 million years) Second Half-Life (1.4 billion years)

6. Fossil Record • Fossils are evidence that an organism lived on Earth. • It is difficult for an organism to become a fossil. • A dinosaur dies in a river. • Sediments quickly cover the remains. • The sediments compress the organism. • Minerals replace the bony material. 4 3 1 2 5

7. A Trip Through Time • Earth’s Timeline is divided into four major eras: • Precambrian Time • Paleozoic Era • Mesozoic Era • Cenozoic Era

8. How Big is a BILLION? • To reach $1Billion saving $100 a day: • 27,397.26 years • Take a Billion step hike: • 378,787.87 miles • 15 laps around the Earth’s equator • Make a Journal with each day on a page: • 4,600,000,000 page • 145 miles long

9. Precambrian Time • About 4.6 bya: • The Earth forms • Surface is very hot and constantly hit with meteors. • Many volcanoes emit lava and gases. • Helps to form the early atomosphere.

10. Precambrian Time • Archaen Period (4.6 bya) • About 4.4 bya: • The Earth’s surface cools. • Water vapors in the atmosphere condense to fill the ocean basins. • About 3.9 bya: • The oldest rocks on Earth today date to this time.

11. Precambrian Time • About 3.4 bya: • Earliest signs of fossilized life. • Early Prokaryotes • Proterozoic (2.5 bya) • About 2.1 bya: • Eukaryotes are found • Multicellular organisms will be seen by the end of the era.

12. Paleozoic Era • 543 mya – 248 mya • Divided up into discreet periods • Major events in vertebrate evolution including the appearances of: • Jawless fishes • Jawed fishes • Lobed-fin fishes • Amphibians • Reptiles

13. Paleozoic Era Opabinia • Cambrian Period • 543 mya – 490 mya • Age of the Trilobites • Cambrian Explosion • Major diversification of life. • All modern body plans originate here. • First vertebrate animals Anomalocaris

14. Paleozoic Era • Ordovician Period • 490 mya – 443 mya • Early Fishes

15. Paleozoic Era • Silurian Period • 443 mya – 417 mya • Fish dominate the seas • Plants and arthropods appear on the land.

16. Paleozoic Era • Devonian Period • 417 mya – 354 mya • The Age of Fishes • First Sharks • Boney Fish • The First Amphibians • First tetrapods that spend time on land • Must return to water to lay eggs Tiktaalik

17. Paleozoic Era • Carboniferous Period • 354 mya – 290 mya • Winged insects appear • First Reptiles • Develop an amniotic egg • No longer needs to return to the water • Appalachian Mountains form

18. Paleozoic Era • Permian Period • 290 mya – 248 mya • The Age of Amphibians • Continents are moving together. • Permian Mass Extinction • 90% of all marine animals die out. • 70% of all land animals die out.

19. Mesozoic Era • From 248 mya to 65 mya • The Age of Reptiles • The Appearance and Extinction of Dinosaurs

20. Mesozoic Era • Triassic Period • 248 mya – 206 mya • The supercontinent, Pangea, is formed. • First Dinosaurs • The first small mammals

21. Mesozoic Era • Jurassic Period • 206 mya – 144 mya • Dinosaurs rule the land • Ichtyosaurs and sharks rule the oceans • Flying dinosaurs and early birds take to the air.

22. Mesozoic Era • Cretaceous Period • 144 mya – 65 mya • Well-known dinosaurs are on earth. • Triceratops • T. Rex • K-T Boundary • Mass extinction events kills all dinosaurs. • Probably caused by meteor impact.

23. Cenozoic Era • From 65 mya to Present • The Age of Mammals • The rise of mammal orders. • The rise of Homo sapiens and our culture.

24. Cenozoic Era • Tertiary Period • 65 mya – 1.8 mya • Mammals take control of the land. • All groups of mammals are now present. • Primates evolve • Gastornis rules the forests . • Known as the Terror Bird Primates Monotremes Carnivores Marsupials

25. Cenozoic Era • Quaternary Period • 1.8 mya – Present • Humans and their ancestors migrate out of Africa to all regions of the Earth. Smilodon (2.5 M– 8,000 YA) Mammoth (4.5 – 0.5 MYA) Last Ice Age ended 10,000 years H. neandertalis 230,000 – 30,000 YA H. erectus 1.8 M – 70,000 YA H. sapiens 250,000 – present

26. What scientific ideas describe the origins of life? Biogenesis Section 14.2

27. Section Objectives • At the end of this lesson, you will be able to: • Analyze early experiments that support the concept of biogenesis. • Review, analyze, and critique modern theories of the origin of life. • Relate hypotheses about the origin of cells to the environmental conditions of early Earth. • Important Vocabulary • Spontaneous Generation • Biogenesis • Protocell • Archaebacteria

28. The Early Ideas • Spontaneous Generation • The idea that nonliving material can produce life. • Rotting meat produces maggots. • Mud puddles produce fish. • Francisco Redi’s Experiment • Placed meat into two groups of jars: half covered; half uncovered. • Maggots were only found on the uncovered meat. • Disproved spontaneous generation.

29. http://www.brooklyn.cuny.edu/bc/ahp/CellBio/Growth/graphics/Microbes.GIFhttp://www.brooklyn.cuny.edu/bc/ahp/CellBio/Growth/graphics/Microbes.GIF http://www.chemheritage.org/EducationalServices/pharm/antibiot/activity/spapas/pasteur3.gif The Early Ideas • Louis Pasteur’s Experiment • Scientists still believed microorganisms arose spontaneously. • Pasteur’s experiment showed that life arises from other organisms, not a vital force in the air. • Biogenesis • The idea that living organisms come only from other living organisms.

30. The Modern Ideas • How did life begin on Earth? • No definitive answer, but a lot of interesting ideas. • Common Theme • Simple organic molecules must have formed. • Monomers • These simple molecules must have organized to form more complex organic structures. • Polymers

31. The Origins of Life Oparin’s Hypothesis • Organic Molecules • The Early Atmosphere was composed of Water Vapor (H2O), Carbon Dioxide (CO2), Nitrogen, Methane and Ammonia. • Energy from the sun, lightning and Earth’s heat generated simple molecules. • Heavy rains washed the molecules into the primordial oceans.

32. The Modern Ideas • Miller and Urey Experiment • Simulated the conditions of early Earth in a lab. • Mixed hydrogen, methane, ammonia and water vapor. • Cooled the gases to condense the mixture and simulate rain. • Added electrical energy to simulate the sun and lightning. • The Results • Several kinds of amino acids, sugars and other small organic molecules were in the solution.

33. H2O CO2 Ammonia Methane Water Flask The Miller and Urey Experiment Water Vapor Electricity Water Vapor Condenser • Analysis: • Amino Acids • Sugars • Lipids, etc HEAT

34. “Simulation” Energy O H H H H H C H H H

35. The Origins of Life • Protocells • By heating solutions of amino acids, scientists produced a protocell: • A large, ordered structure, enclosed by a membrane. • Carries out some life activities like growth and division.

36. The Origins of Life • Early Prokaryotes (3.4 bya) • Archaebacteria • Prokaryotes which live in harsh environments (deep-sea vents and hot springs) • Use chemosynthesis to produce glucose. • Photosynthesis • Cyanobacteria • Photosynthesis releases oxygen into the atmosphere. • Open to aerobic respirating bacteria.

37. The Origins of Life Endosymbiont Theory • Eukaryotes • Complex eukaryotic cells evolved from close relationships of ancient prokaryotes. • Mitochondria • Chloroplasts

38. The Origins of Life • Multicellular Organisms • Eukaryotes organize into tissues and multicellular life forms: • Allows plants, fungi and animals to develop. • From the animals, fish emerge first • without jaws and then with • Cartilage and then bones • Ray-fins and then lobe-fins • Lungs develop • Limbs develop • Amphibians  Reptiles (including birds) Mammals

39. The Origin of Life 1.0 bya 2.1 bya Multicellular Organisms 3.4 bya Eukaryotes Early Prokaryotes Protocells Organic Molecules 4.6 bya