Lectures 22, 23: GY 112: Earth History Paleozoic Overview & the Cambrian Explosion
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UNIVERSITY OF SOUTH ALABAMA GY 112: Earth History Lectures 22, 23: Paleozoic Overview & the Cambrian Explosion Instructor: Dr. Douglas W. Haywick Last time we covered (before the exam)… 1) 2) Eukaryotes (Acritarchs) Metazoans (Ediacarin Fauna) Proterozoic Fossils During the Archean, we saw the rise of the prokaryotes: •Small •No nucleus •DNA spread throughout the cell •Asexual reproduction •Could only be single-celled Proterozoic Fossils During the Proterozoic, something wonderful happens: the rise of the eukaryotes: •Larger (>0.06 mm) •A nucleus and organelles •DNA contained within the nucleus •Sexual reproduction •Could be multi-celled (metazoans) Proterozoic Fossils The first eukaryotes appeared around 2 GA. Acritarchs were small, single celled silica beasties that floated in the oceans (pelagic). They peaked in abundance at 750 MA and then went away… 0.1mm Proterozoic Fossils They are known as the Ediacarin Fauna And they are found around the world http://www.snowballearth.org/end.html http://www.cartage.org.lb/en/themes/Sciences Proterozoic Fossils More likely, severe environmental changes drives evolutionary adaptation. We need bad things to happen in order to evolve. Today’s Agenda Paleozoic Overview 1) Time Frame 2) World Paleogeography 3) Key Tectonic events The Cambrian Explosion 1) Why a Cambrian “explosion” 2) Introducing our ancestors (GY 112 lab stuff) (web notes 22, 23) Phanerozoic Time Frame Eon Time Phanerozoic 550 MA to 0 MA Proterozoic 2.5 GA to 550 MA Archean 4.1 GA to 2.5 GA Hadean 4.6 GA to 4.1 GA Phanerozoic Time Frame Years Cenozoic (0 to 65 MA) Mesozoic (65 to 245 MA) Paleozoic (245 to 550 MA) Phanerozoic Phanerozoic Era Paleozoic Time Frame Era Period Permian (245 to 286 MA) Pennsylvanian (286 to 320 MA) Mississippian (320 to 362 MA) Paleozoic Devonian (362 to 418 MA) Silurian (418 to 441 MA) Ordovician (441 to 505 MA) Cambrian (505 to 550 MA) NeoProterozoic American System Paleozoic Time Frame Era Period Era Period Permian (245 to 286 MA) Permian (245 to 286 MA) Pennsylvanian (286 to 320 MA) Carboniferous (286 to 362 MA) Mississippian (320 to 362 MA) Paleozoic Devonian (362 to 418 MA) Paleozoic Devonian (362 to 418 MA) Silurian (418 to 441 MA) Silurian (418 to 441 MA) Ordovician (441 to 505 MA) Ordovician (441 to 505 MA) Cambrian (505 to 550 MA) Cambrian (505 to 550 MA) NeoProterozoic American System NeoProterozoic World System Paleozoic Time Frame Era Period Era Period Permian (245 to 286 MA) Permian (245 to 286 MA) Pennsylvanian (286 to 320 MA) Carboniferous (286 to 362 MA) Mississippian (320 to 362 MA) Paleozoic NeoProterozoic Devonian (362 to 418 MA) Paleozoic Devonian (362 to 418 MA) Silurian (418 to 441 MA) Silurian (418 to 441 MA) Ordovician (441 to 505 MA) Ordovician (441 to 505 MA) Cambrian (505 to 550 MA) Cambrian (505 to 550 MA) Ediacaran (600 to 550 Ma) American System NeoProterozoic Ediacaran (600 to 550 Ma) World System Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic Paleogeography Laurentia Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic Paleogeography Paleozoic video insert Paleozoic Tectonics (Key World Events) Period Permian North America Europe Asia/Gondwanna Alleghenian Orogeny* (SE) Hercynian Orogeny Ural Orogeny Pensylvannian Mississippian Ouachita Orogeny (S) Devonian Acadian Orogeny* (E) Antler Orogeny (W) Ouachita equivalent (South America) Caledonian Orogeny Silurian Ordovician Cambrian Taconic Orogeny* (NE) Broad deformation (Southern Gondwanna) The Cambrian Explosion Not so much an explosion… The Cambrian Explosion Not so much an explosion… …more of a shift… The Cambrian Explosion Not so much an explosion… …more of a shift… to hard body parts http://arjournals.annualreviews.org/na101/home/literatum/publisher/ The Cambrian Explosion The Cambrian Explosion The Cambrian Explosion What we know about the early development of all of the current phyla is limited to sites where we have lots of beasties preserved http://arjournals.annualreviews.org/na101/home/literatum/publisher/ The Cambrian Explosion Burgess Shale Fauna Chengjiang Fauna What we know about the early development of all of the current phyla is limited to sites where we have lots of beasties preserved http://arjournals.annualreviews.org/na101/home/literatum/publisher/ The Burgess Shale The Burgess Shale Burgess Shale Site The Burgess Shale Burgess Shale Site The Burgess Shale The Burgess Shale The Burgess Shale The Burgess Shale The Burgess Shale The Burgess Shale http://www.hao.ucar.edu/Public/models/pikaia/pikaia.gif Pikaia gracilens (phylum: Chordata) The Burgess Shale http://www.hrw.com/science/si-science/biology/animals/burgess/phallu.html Hallucigenia sparsa (phylum: Arthropoda) http://www.karencarr.com/Images/Gallery/2004_gallery_hallucigenia.jpg The Burgess Shale Limb Anomalocaris canadensis (phylum: Arthropoda?) (Proto-Arthropod; Problematica) http://www.search4dinosaurs.com/burgess_shale.jpg The Burgess Shale http://www.hrw.com/science/si-science Jaws Anomalocaris canadensis (phylum: Arthropoda?) (Proto-Arthropod; Problematica) http://www.search4dinosaurs.com/burgess_shale.jpg The Burgess Shale http://home.earthlink.net/~airdpacoima/sitebuildercontent/sitebuilderpictures/burgess__s.jpg Paleozoic Life Forms Your Responsibilities Reminder: You are going to have to become familiar with some of the major fossil groups (AKA Taxonomy). Your Responsibilities Know the stuff in bold text for the lab test Phylum Sub-divisions Porifera Cnidaria Class: Anthozoa Subclass: Zoantharia Subclass: Tabulata Subclass: Rugosa Bryozoa This chart is on line (there is no need to write everything down!) Common names Age Ranges Sponges Cambrian-Recent Corals & Anemones Scleratinian corals Tabulate corals Rugose (horn) corals Triassic-Recent Cambrian-Permian Ordovician-Permian Bryozoans Ordovician-Recent Brachiopoda Class: Inarticulata Class: Articulata Inarticulate brachiopods Articulate brachiopods Cambrian-Recent Cambrian-Recent Arthropoda Subphylum: Trilobita Subphylum: Crustacea Subphylum: Unirama Class: Myriapoda Class: Hexapoda Class: Arachnidea Trilobite crabs, lobsters etc. millipedes, centipedes Insects Spiders Cambrian-Permian Cambrian-Recent Mississippian-Recent Devonian-Recent Devonian-Recent Phylum Know the stuff in bold text for the Final lab test Sub-divisions Common names Age Ranges Mollusca Class: Amphineura Class: Scaphopoda Class: Gastropoda Class: Bivalvia Class: Cephalopoda Order: Nautiloidea Order: Ammonoidea Order: Belemnoidea Order: Octopoda chitons tusk shells snails bivalves (clam shells) Nautiloids Ammonites Belemnites Octopi Cambrian-Recent Cambrian-Recent Cambrian-Recent Cambrian-Recent Cambrian-Recent Cambrian-Recent Dev.-Cretaceous Miss.-Early Tertiary Echinodermata Class: Asteroidea Class: Echinoidea Class: Crinoidea Class: Blastoidea Class: Cystoidea Starfish Urchin, biscuit, dollar crinoids blastoids cystoids Ordovician-Recent Ordovician-Recent Cambrian-Recent Silurian-Permian Cambrian-Devonian Hemichordata Class: Graptolithina Order: Graptoloidea Order: Dendroidea graptolites dendroids Cambrian-M. Ordovician-Silurian Cambrian-M. Chordata Subphylum: Vertebrata Class: Agnatha Class: Acanthodii Class Placodermi Class: Osteichthyes Class: Chondrichthyes Class: Amphibia Class: Reptilia Subclass: Anapsida Subclass: Synapsida Subclass: Lepidosauria Subclass: Archosauria Class: Aves Class: Mammalia (Chordates with bones) jawless fish Primitive jawed fish Plated, bony jawed fish Bony jawed fish Sharks and rays Amphibians Reptiles includes turtles mammal-like reptiles Lizards and snakes dinosaurs & crocodiles Birds mammals Cambrian-Recent Silurian-Permian Silurian-Devonian Silurian-Recent Devonian-Recent Devonian-Recent Mississippian-Recent Mississippian-Recent Penn.-Jurassic Permian-Recent Triassic-Recent Jurassic-Recent Triassic-Recent Today’s Homework 1. Quiz 8 next time (multiple choice) 2. Time Chart 2 (Due Thursday April 3rd) (Hadean-end of Proterozoic) Next Time Paleozoic Geology Part 1 GY 112: Earth History Lectures 22, 23: Paleozoic Overview/ Cambrian Explosion Instructor: Dr. Doug Haywick dhaywick@southalabama.edu This is a free open access lecture, but not for commercial purposes. For personal use only.
