Lectures 22, 23: Paleozoic Overview & the Cambrian Explosion

UNIVERSITY OF SOUTH ALABAMA

GY 112: Earth History Lectures 22, 23: Paleozoic Overview & the Cambrian Explosion

Instructor: Dr. Douglas W. Haywick Last time (before Spring Break)…

Proterozoic Fossils 1) Eukaryotes (Acritarchs) 2) Metazoans (Ediacarin Fauna)

(web notes 21) 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 Phanerozoic Time

Phanerozoic Paleozoic Cenozoic Mesozoic

Phanerozoic Era

(245 to 550 MA) to(245 (65245 MA) to (0 to 65 MA)

Years

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) Neo- Proterozoic American System Paleozoic Time Frame

Era Period Era Period Permian Permian (245 to 286 MA) (245 to 286 MA)

Pennsylvanian (286 to 320 MA) Carboniferous (286 to 362 MA) Mississippian (320 to 362 MA) Paleozoic Devonian Paleozoic Devonian (362 to 418 MA) (362 to 418 MA) Silurian Silurian (418 to 441 MA) (418 to 441 MA) Ordovician Ordovician (441 to 505 MA) (441 to 505 MA) Cambrian Cambrian (505 to 550 MA) (505 to 550 MA) Neo- Neo- Proterozoic Proterozoic American System World System Paleozoic Time Frame

Era Period Era Period Permian Permian (245 to 286 MA) (245 to 286 MA)

Pennsylvanian (286 to 320 MA) Carboniferous (286 to 362 MA) Mississippian (320 to 362 MA) Paleozoic Devonian Paleozoic Devonian (362 to 418 MA) (362 to 418 MA) Silurian Silurian (418 to 441 MA) (418 to 441 MA) Ordovician Ordovician (441 to 505 MA) (441 to 505 MA) Cambrian Cambrian (505 to 550 MA) (505 to 550 MA) Neo- Ediacaran Neo- Ediacaran Proterozoic (600 to 550 Ma) Proterozoic (600 to 550 Ma) American System 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 North America Europe Asia/Gondwanna Permian Alleghenian Orogeny* Hercynian Orogeny Ural Orogeny (SE) Pensylvannian Mississippian Ouachita Orogeny (S) Ouachita equivalent (South America)

Devonian Acadian Orogeny* (E) Caledonian Orogeny Antler Orogeny (W)

Silurian

Ordovician Taconic Orogeny* (NE)

Cambrian 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

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

Phylum Sub-divisions Common names Age Ranges Know the stuff Porifera Sponges Cambrian-Recent in bold text for Cnidaria Class: Anthozoa Corals & Anemones Triassic-Recent the lab test Subclass: Zoantharia Scleratinian corals Cambrian-Permian Subclass: Tabulata Tabulate corals Ordovician-Permian Subclass: Rugosa Rugose (horn) corals Bryozoa Bryozoans Ordovician-Recent

This chart is on line Brachiopoda Class: Inarticulata Inarticulate brachiopods Cambrian-Recent Class: Articulata Articulate brachiopods Cambrian-Recent (there is no need to Arthropoda Subphylum: Trilobita Trilobite Cambrian-Permian Subphylum: Crustacea crabs, lobsters etc. Cambrian-Recent write everything Subphylum: Unirama millipedes, centipedes Mississippian-Recent Class: Myriapoda Insects Devonian-Recent down!) Class: Hexapoda Spiders Devonian-Recent Class: Arachnidea Phylum Sub-divisions Common names Age Ranges

Mollusca Class: Amphineura chitons Cambrian-Recent Class: Scaphopoda tusk shells Cambrian-Recent Class: Gastropoda snails Cambrian-Recent Class: Bivalvia bivalves (clam shells) Cambrian-Recent Class: Cephalopoda Nautiloids Cambrian-Recent Order: Nautiloidea Ammonites Cambrian-Recent Order: Ammonoidea Belemnites Dev.-Cretaceous Know the Order: Belemnoidea Octopi Miss.-Early Tertiary Order: Octopoda stuff in bold Echinodermata Class: Asteroidea Starfish Ordovician-Recent Class: Echinoidea Urchin, biscuit, dollar Ordovician-Recent text for the Class: Crinoidea crinoids Cambrian-Recent Class: Blastoidea blastoids Silurian-Permian Final lab test Class: Cystoidea cystoids Cambrian-Devonian Hemichordata Class: Graptolithina graptolites Cambrian-M. Order: Graptoloidea dendroids Ordovician-Silurian Order: Dendroidea Cambrian-M. Chordata Subphylum: Vertebrata (Chordates with bones) Cambrian-Recent Class: Agnatha jawless fish Silurian-Permian Class: Acanthodii Primitive jawed fish Silurian-Devonian Class Placodermi Plated, bony jawed fish Silurian-Recent Class: Osteichthyes Bony jawed fish Devonian-Recent Class: Chondrichthyes Sharks and rays Devonian-Recent Class: Amphibia Amphibians Mississippian-Recent Class: Reptilia Reptiles Mississippian-Recent Subclass: Anapsida includes turtles Penn.-Jurassic Subclass: Synapsida mammal-like reptiles Permian-Recent Subclass: Lepidosauria Lizards and snakes Triassic-Recent Subclass: Archosauria dinosaurs & crocodiles Jurassic-Recent Class: Aves Birds Triassic-Recent Class: Mammalia mammals Today’s Homework

1. Study!

Next Time

Lecture Test 2 GY 112: Earth History

Lectures 22, 23: Paleozoic Overview/ Cambrian Explosion

Instructor: Dr. Doug Haywick [email protected]

This is a free open access lecture, but not for commercial purposes. For personal use only.