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Chapter 17 The History of Life. Section 17-3 Evolution of Multicellular Life. The Fossil Record. Documents Evolutionary Histories Climate Geography Life Forms. Precambrian Time. Covers 90% of Earths History During This Period: Simple Anaerobic Life Formed Then Photosynthetic Organisms
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Chapter 17The History of Life Section 17-3Evolution of Multicellular Life
The Fossil Record • Documents • Evolutionary Histories • Climate • Geography • Life Forms
Precambrian Time • Covers 90% of Earths History • During This Period: • Simple Anaerobic Life Formed • Then Photosynthetic Organisms • Released Oxygen • Aerobic Life Formed • Eukaryotes Developed • Multicellular Organisms Appeared Start Finish
Paleozoic Era Key Concept: Early In The Paleozoic Era, The Fossil Record Became Rich With Evidence of Many Types of Marine Life Paleozoic Weblink Age of the Trilobites
Cambrian Period • Cambrian Explosion • Huge Numbers of Multicellular Life Forms Developed • Shells, Outer Skeletons, Appeared • Trilobites, Brachiopods, Invertebrates Arrived • Burgess Shale in British Columbia is a famous fossil site for this event
Ordovician & Silurian Periods • First Appearance of: • Octopus, Squid • Aquatic Arthropods • Vertebrate • Jawless Fishes (suckers) • Insects • Plants
Devonian Period Ferns Appear Fish Proliferate Sharks Appear Amphibians Evolve
Devonian Period Key Concept: During The Devonian, Animals Began To Invade Land
Carboniferous & Permian Periods • Life Expands Across The Continents • Reptiles • Winged Insects • Dragonflies, Cockroaches • Giant Ferns, Swampy Forests • Laid Down Coal Deposits
Carboniferous & Permian Periods Key Concept: The Mass Extinction At The End Of The Paleozoic Affected Both Plants & Animals On Land & In The Seas. 95% Of Complex Ocean Life Forms Disappears
Permian Extinction • Killed Off • Trilobites • Many Amphibians • What Survived • Most Fishes • Numerous Reptiles Extinction Link
Mesozoic Era Key Concept: Events During The 180 Million Years Of The Mesozoic Era Include The Increasing Dominance Of Dinosaurs. The Mesozoic Is Marked By The Appearance Of Flowering Plants
Triassic Period • Made Up Of The Organisms That Survived The Permian Extinction • Cone Bearing Plants Appear • “AGE of REPTILES”
Triassic Period • Mammals Appear In The Late Triassic • Small Shrewlike Organisms
Jurassic Period Dinosaurs Still Rule First Birds Appear Archaeopteryx
Cretaceous Period • Dinosaurs Still Dominant • T. rex • Flying Reptiles • Became Extinct During Cretaceous • Seas Contained • Turtles • Crocodiles • Plesiosaurs
Cretaceous • Appearance of: • Leafy Trees • Shrubs • Small Flowering Plants • True Seeds • Often Enclosed In Fruit
Cretaceous Extinction • 65 Million Years Ago • > 50% of All Plant & Animal Groups Wiped Out • Including ALL the Dinosaurs
Cenozoic Era The Age of Mammals Key Concept: During The Cenozoic, Mammals Evolved Adaptations That Allowed Them To Live In Various Environments – On Land, Water & Air.
Tertiary Period • Climates Warm & Mild • Whales & Dolphins Evolve • Grasses Evolve • Grazing Animals Evolved • Some Mammals & Birds Became Very Large
Quaternary Period • Climate Cooled • Several Ice Ages Occurred • Sea Levels Dropped By Over 100 Meters (300 Feet) • 20,000 Years Ago • Climate Warmed • Ice Packs Melted • Sea Level Returned
Quaternary Period • 4.5 Million Years Ago • Our Primate Ancestors Evolved • 100,000 Years Ago • Genus Homo Arose In Africa • Migrated Across The World