Notes for Lecture #11:

        The History of Life

        Copyright 1996. May not be reproduced for commerical purposes

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        You will be required to know all the details on the geologic timetable . This can also be found on page 8 of your lab manual

        Some other references

        • R. Cowen. 1990. History of life. Blackwell.
        • C. L. and M. A. Fenton. 1989. The fossil book. Doubleday.
        • S. J. Gould. 1989. Wonderful life. Norton.
        • Time Dec 4, 1995 (cover story) Evolution's big bang

        The geologic timetable

        • Geological time system arranged in a hierarchic fashion

        The major Eons

        • Precambrian Eon (590 MY - 4.5 BY ago)

          • From the formation of the earth to the explosion of multicellular life

        • Phanerozoic Eon (590 MYA to present)

          • The diversification of multicellular life

        Precambrian Eon

        Phanerozoic Eon

        • Paleozoic Era

          • 590 -248 MYA

          • Fishes and amphibians

        • Mesozoic Era

          • 248 - 65 MYA

          • Dinosaurs dominate

        • Cenozoic Era

          • 65 MYA - present

          • mammals dominate

        Cambrian Period 590-505 MYA

        • Explosive evolution of most major phyla

        • Mass extinction event at Cambrian-Ordovician boundary

        • The burgess Shale

        Amiskwia

        Anomalocaris

        Hallucigenia

        Nectocaris

        Odonotgriphus

        Ordovician Period 505-438 MYA

        • Tribotes most numerous

        • Primative jawless fishes

        • Nautiloids common

        Silurian Period 438-408 MYA

        • Fish diversify, first jawed fishes

        • Pteraspis

        • Herricyclaspis

        • Plants colonize the land

        • Sea Scorpins (here Eurypterus ) roam the oceans

        Devonian Period 408-360 MYA

        The Age of fishes

        • Climatius

        • Eusthenopteron

        • Tribolites still common

        • Ceratarges

        • Terataspis

        Carboniferous Period 360-280 MYA

        Amphibians and Reptiles appear on land

        • Diplocaulus

        • Vast forests appear on land

        Permian Period 280-248 MYA

        • Conifers appear

        • Amphibians and reptiles diversify

        • Cacops

        • Eryops

        Mesozoic Era

        Triassic Period 248-213 MYA

        • Extinction of trilobites

        • Mammals and dinosaurs appear

        • Megazostrodon

        • Thrinaxodon, a mammal-like reptile in Antartica

        Jurassic Period 213-144 MYA

        Dinosaurs diversity

        Cretaceous Period 144-65 MYA

        • Angiosperms appear and become the dominate terrestrial plant form

        • Mass extinction at Cretaceous-Tertiary boundary, evidence of extra-terrestrial impact

        • Archaeopteryx, first fossil bird, appears

        • Pterosaurs

        • Tylorsaurus

        Cenozoic Era

        Age of mammals

        • Tertiary Period 65 - 2.5 MYA

        • Quaternary Period 2.5 MYA - present

        Tertiary Period 65 - 2.5 MYA

        • Paleocene Epoch 65 -55 MYA

        • Eocene Epoch 55 -38 MYA

          Some Eocene mammals

          • Basalosaurs

          • Prozoughtodon

          • Notharcutus

        Oligocene Epoch 38 -26 MYA

        • Florissant fossil beds, famous for fossil insects

        Miocene Epoch 26 - 6 MYA

        • Earliest primates

        • Mid-ploiocent (3.6-3.1 MYA), North and South Anerican exchange fauna

        Pliocene Epoch 6-2.5 MYA

        • Origin of hominids

        Quaternary Period 2.5 MYA - present

        • Pleistocene Epoch 2.5 MYA - 10,000 years ago

          • Origin of Homo

        • Recent Epoch 10,000 years ago - present