Chapter 10 - Life of the Paleozoic

I.	Overview of Life Expansion
	A.  Cambrian:  Vast expansion of shells marine life forms in contrast to all earlier
	life
	B.  Ordovician:  Most modern phyla established by this time
	C.  Late Paleozoic:  Land plants and vertebrates are very successful in populating
	the continents

II.	Plants of the Paleozoic
	A.  Cambrian:  Stromatolites and stromatolitic reefs
	B.  Ordovician to Silurian:  Receptaculids (green alga) of Dasycladaea or
	"sunflower corals"
	C.  Early Paleozoic:  Chlorophytes and fungi formed lichens
	D.  Ordovician:  Primitive 4-spore tracheophytes (vascular plants) and bryophytes
	(mosses, etc.)
	E.  Silurian:  3-spore tracheophytes
	    1.  Effects of land plants
		a.  roots slowed erosion
		b.  transpiration
		c.  shelter for animals
		d.  leaf litter decay (true soils)
	    2.  First unquestioned vascular structure in plants:  Middle Silurian (psilophytes)
		a.  up to 30 cm tall
		b.  horizontal stalks (rhizones)
		c.  vertical stems and spore sacs
	F.  Late Devonian:  Forests of well rooted trees (7m tall)
	G.  Devonian-Pennsylvanian trends
	    1.  evolved efficient reproduction (seedless) first
	    2.  Then seedless, pollinating, non-flowering
	    3.  eventually seeds and flowers evolved in Mesozoic
	H.  Carboniferous (Mississippian - Pennsylvanian) Scale Trees
	    1.  Lycopsids (survivor = modern club mosses) like Lycopodium (small ground
	    pine)
	    2.  Lepidodendron:  Forked branches 30m tall, diagonal spiral leaf scars on
	    branches
	    3.  Sigilaria:  Leaf scars in parallel rows
	    4.  Sphenopsids (scouring rushes and horsetails) like Calimites and Annularia:
	    Slender, unbranching ribbed stems with thick core
	I.  Carboniferous Ferns and Seed Ferns
	    1.  True ferns (spore bearing)
	    2.  Seed ferns (not true ferns, leaves were fern-like):  Glossopteris
	J.  Permian:  Primitive conifers and others
	    1.  Cordiates:  Up to 50 m tall, strap-like leaves
	    2.  Ginkgo:  Appeared in drier climates
	    3.  End-Permian extinction's:  Several plant groups

III.	Invertebrates of the Paleozoic:  Arrival of Animals with Shells
	A.  Review of modes of life in marine realm
	    1.  Location:  Nektic, planktic bentic
	    2.  Adaptation:  Epifaunal, infaunal, mobile
	    3.  Feeding strategy:  Filter-feeders, sediment-feeders
	B.  Review of significant Proterozoic (Ediacaran) fossils
	    1.  Cloudina
	    2.  soft-bodied fossils
	C.  Tommotian (Earliest Cambrian) fossils of note from Siberia, Sweden, N.
	America, Antarctica, and England
	    1.  Shells and elements of tiny mollusks, sponges, and cap-shaped tubular shells
	    (calcium carbonate or phosphate)
	    2.  Anabaritids:  Tubular fossils (3 tubes joined together, each tube has a keel)
	    3.  Lapworthella:  Cap shaped and ornamented
	D.  Extraordinary Early Cambrian Soft Body Fossil Sites
	    1.  Chengjian site, China
		a.  10 m.y. older than Burgess Shale
		b.  Cathaymyrus:  V-shaped muscles; notochord; gill slits
	    2.  Burgess Shale, British Columbia Canada
		a.  viewed as one of the most important faunas in fossil record
		b.  impressions and films of bedding planes
		c.  limited exposure near MT. Wapta, BC
		d.  discovered by C.D. Walcott in 1909
	E.  Burgess Shale Fauna
	    1.  4 Group of arthropods
		a.  trilobites
		b.  crustaceans
		c.  scorpions
		d.  insects
	    2.  Other taxonomic groups
		a.  sponges
		b.  onycophorans
		c.  crinoids
		d.  sea cucumbers
		e.  chordates
		f.  unknowns
	    3.  Significance of chordates (Whittington, 1960-1975)
		a.  shows evolution of early notochord
		b.  dorsally situated nerve chord
		c.  notochord is precursor of vertebral column
		d.  fossil Pikaia:  Notochord and V-shaped muscle bands for sinuous
		swimming motion
		e.  Pikaia and others are ancestors of all modern vertebrates
	    4.  Notable fossils in Burgess Shale
		a.  Anomalocaris:  Fierce predator over 50 cm long, stalked eyes, many
		teeth
		b.  Opabinia:  5 eyes, flexible nozzle with nippers
		c.  Hallucigenia:  7 pairs of legs, 7 pairs of dorsal spines, claws, cylindrical
		trunk (may be an onycophran)
		d.  Marrella:  4 spines extend back from cephalon

IV.	Invertebrates of the Paleozoic:  Diversification
	A.  Unicellular groups
	    1.  Foraminifera (calcareous microfossils)
		a.  range Cambrian to present
		b.  more numerous and varied by Carboniferous
		c.  global distribution in Pennsylvanian-Permian
	    2.  Radiolarians (siliceous microfossils)
		a.  range Early Paleozoic to present
		b.  most abundant in Mesozoic rocks
	B.  Cup Animals:  Archaeocyathids
	    1.  conical or vase-shaped skeletons
	    2.  extinct phylum by end of Cambrian
	    3.  earliest reef builders
		a.  N. America, Siberia, Antarctica, Australia
		b.  Australian reefs: 60m x 200km
	C.  Pore-Bearers:  Porifera (sponges)
	    1.  Well known guide fossils
		a.  Cambrian: Protospongia
		b.  Silurian:  Astaeospongium, Microspongia, and Astylospongia
		c.  Devonian:  Hydnoceras
	    2.  Main taxonomic groups
		a.  Desmospongea:  Spongin
		b.  Hexactinellida:  Siliceous spicules
		c.  Calcarea:  Calcium carbonate spicules
	    3.  Main parts of modern sponge
		a.  osculum
		b.  choanocytes
		c.  mesenchyme
		d.  flagellae
	    4.  Early Paleozoic stromatoporoids (Silurian-Devonian)
		a.  fibrous calcareous skeletons in pillars
		b.  massive reef-forming
	D.  Corals and other Cnidaria
	    1.  main groups
		a.  sea anemones
		b.  sea fans
		c.  jellyfish
		d.  Hydra
		e.  reef-forming corals
	    2.  Main layers
		a.  ectoderm
		b.  endoderm
		c.  mesoglea
	    3.  Body form:  Polyp or medusa
	    4.  Anthozoa (stony corals):  Polyp secrets in cup
		a.  theca (cup) divided by vertical plates (septa)
		b.  tabulae (horizontal growth plates in theca)
	    5.  Rugose versus tabulate corals
		a.  rugose have septa at 4 locations (modern scleractinian corals have 6)
		b.  tabulate corals have obscure septa, tabulae are dominant (e.g.
 		honeycomb and chain corals)
	    6.  Range of Cnidaria
		a.  jellyfish:  Proterozoic to present
		b.  lime secreting anthozoans:  Ordovician expansion
		c.  Favorite sites:  Tabulate (honeycomb) coral of Silurian
		d.  rugose:  Devonian-Carboniferous, extinct in Late Permian
	    7.  Stony corals:  Key reef builders of Paleozoic
	E.  Moss Animals:  Bryozoans
	    1.  Format:  Minute, bilaterally symmetrical colonial, "twig-like" macroscopic
	    appearance
	    2.  Sooecium - individual fossil living site
	    3.  Zooarium - fossil colony
	    4.  Range:  Lower Ordovician to present
	    5.  Paleozoic forms:  Common in reefs
		a.  Fistulipora:  Encrusting or arborescent
		b.  Hallopora:  Branching zooarium
		c.  Constellaria:  Star-shaped patterns of zooecia
		d.  Archimedes:  Corkscrew (?) fenertelled colony (Mississippian)
	F.  Brachiopods (most abundant, diverse and useful Paleozoic fossil group)
	    1.  Format:  Bivalves symmetrical across the valve (shell); valves are dorsal and
	    ventral
	    2.  Mineral makeup:  Calcium carbonate (most taxa), chitin, calcium phosphate
	    3.  Articulate brachiopods:  Valves hinged along posterior margin (teeth and
	    sockets; commonly ribbed or ornamented)
		a.  first occurred in Cambrian
		b.  flourished in Ordovician
		c.  common in Late Paleozoic
		d.  persist today
	    4.  Inarticulate brachiopods:  Valves held by muscles
		a.  commonly chitino-phosphatic
		b.  simple spoon-shaped or circular valves
		c.  major decline in diversity during Ordovician; exist today
	    5.  Feeding and mode of life
		a.  lophophore -  coiled feeding tentacles
		b.  filter feeders
		c.  attached to sessile after larval stage
	    6.  Early Paleozoic articulate brachiopods
		a.  strophomenids
		b.  orthids
		c.  pentamerids
		d.  rhynchonellids
	    7.  Late Paleozoic articulate brachiopods
		a.  spiriferids (especially Devonian)
		b.  productids (especially Carboniferous and Permian)
	G.  Mollusks
	    1.  Main taxa:  Snails, clams, chitons, tooth shells, squids
	    2.  Main physical features in common
		a.  foot
		b.  mantle
	    3.  Primitive Mollusks:  Placophorans
		a.  Monoplacophorans (single shell):  Range Cambrian-Devonian; also a
	"living fossil"
		b.  ancestors of modern pelecypods
	    4.  Bivalvia (clams, oysters, mussels) or Pelecypoda
		a.  range:  first noted in Cambrian; abundant after Carboniferous, exist
		today
		b.  gastropods:  Early Cambrian to present
		c.  cephalopods:  Nautiloidea (simple sutures), Ammonoidea (complex 
		structures)
		d.  only Nautilus exists today
	    5.  Goniatites:  First ammonoid cephalopods appearing in Devonian
	H.  Arthropods
	    1.  Main taxa:  Lobsters, spiders, insects, others
	    2.  Main fossil group:  Trilobites, ostracodes, eurypterids
	    3.  Trilobites
		a.  segments (lobes):  Cephalon, thorax, pygidium
		b.  most abundant and diverse group in Cambrian (over 600 genera)
		c.  index fossils:  Paradoxides (middle Cambrian
		d.  optimal diversity:  Late Cambrian
		e.  decline began in Mid to Late Devonian
		f.  extinction at end of Paleozoic
	    4.  Eurypterids
		a.  scorpion-like bodies with terminal spine, 3m long
		b.  marine and brackish facies
		c.  Ordovician-Permian (abundant during Silurian and Devonian)
		d.  extinct today
	I.  Spiny-skinned Animals:  Echinoderms
	    1.  Main taxa:  Starfish, sea urchins, sea lilies
	    2.  Main fossil classes
		a.  Asteroidea (starfish)
		b.  Ophiuroidea (brittle stars)
		c.  Echinoidea (sea urchins)
		d.  Edrioasteroidea
		e.  Crinoidea (sea lilies)
		f.  Blastoidea
		g.  Cystoidea
	    3.  Primitive ancestral echinoderms
		a.  Arkarua:  Globular form in Ediacaran fauna
		b.  Helicophacus:  Spinde form in Early to Middle Cambrian
	    4.  Stemmed and stalked echinoderms (cystoids)
		a.  first occur in Mid-Cambrian
		b.  stemmed forms are abundant in Ordovician-Silurian and range to Late
		Devonian
		c.  stalked forms (blastoids) appeared in Silurian expanded in 
		Mississippian, and became extinct in Permian
		d.  crinoids:  Calyx, stem, arms
		e.  crinoid range:  Ordovician to present (mostly in Mississippian rocks)
	J.  Graptolites
	    1.  Format:  Colonial chitinous stipes with thecae
	    2.  Range:  Late Cambrian-Mississippian (especially Ordovician-Silurian)
	    3.  Rhabdosome (colony) arranged on a filament
	    4.  Filament features:  nema and sicula
	    5.  Colonies may have been supported by a floating sac
	    6.  May be related to primitive living chordates (pterobranches)
	K.  Continental (Terrestrial) Invertebrates
	    1.  Ordovician:  Millipede trace fossils
	    2.  Silurian:  Arthropod cutcles and bristles; spores; feces
	    3.  Late Silurian:  Centipede and millipede body fossils
	    4.  Devonian:  Mites, wingless arthropods (archaeograths), centipedes,
	    arthropods, gastropods
	    5.  Late Mississippian:  Insects common
	    6.  Pennsylvanian:  Large dragonflies, cockroaches, scorpions, centipedes,
	    arthropods, gastropods

V.	Vertebrates of Paleozoic
	A.  Conodonts (microfossil teeth)
	    1.  Range:  Late Paleozoic-Triassic
	    2.  Fossil hard parts:  Tooth-like calcium phosphate fossils
	    3.  Whole body form:  Eel-like, 40 cm long, a primitive jaw-less vertebrate with
	    many teeth	
		a.  similar to living cephalochordate, Brachiostoma
		b.  Proissum:  Fossil soft body in 500 m(?) shale Ordovician, S. Africa
	B.  Fishes
	    1.  Dermal plates (Upper Cambrian, Wyoming)
	    2.  Scales and plates (Ordovician, Colorado)
	    3.  5 Taxonomic classes
		a.  Agnatha (jaw-less fish)
		b.  Acanthodii and Placodermi (archaic jawed fish)
		c.  Chondrichthyes (cartilaginous fish)
		d.  Osteichthyes (boney fish)
	    4.  Early Paleozoic Agnatha (ostracoderms; extinct in Devonian)
		a.  Theolodus
		b.  Jamoytius
		c.  Pteraspis (armored)
		d.  Hemicyclaspis
	    5.  Early Paleozoic Acanthodii and Placodermi
		a.  arose in Silurian
		b.  most abundant in Devonian (e.g. Dunkleosteus)
		c.  extinct in Permian
	    6.  Early Paleozoic Chondrichthyes (sharks, rays, skates)
		a.  range:  Late Devonian to present
		b.  Cladoselache:  Late Paleozoic shark
		c.  Xenacanthus: Freshwater form,  Late Carboniferous
		d.  Bradyodonts:  Ray like fish
	    7.  Early Paleozoic Osteichthyes(e.g. Cheirolepus, Devonian)
		a.  Actinopterygii:  lobe fins
		b.  Sarcopterygii:  Ray finds
	    8.  Lung fishes of the Devonian
		a.  Dipnoi ("double breather")
		b.  Crossopterygii (e.g. Eusthenopteron)
	C.  Amphibians
	    1.  Ichthyostegids:  Fish-like amphibians
	    2.  Labyrinthodonts:  Teeth similar to ray-fin fishes (e.g. Cacops)
	D.  Reptiles
	    1.  Hyonomus:  Earliest known (Early Pennsylvanian of Nova Scotia); 24 cm
	    long; salamander like form 
	    2.  Petrolacosaurus:  Late Pennsylvanian of Kansas; longer neck and legs than
	    previous; dinosaurian ancestor
	    3.  Pelycosaurs:  Permian sail-black forms; mammalian ancestors
		a.  Edaphosaurus - herbavore
		b.  Dimetrodon - carnivore
	    4.  Theraspids:  Mammal-like reptiles
		a.  Cynognathus - Permian
		b.  range of group:  Permian-Early Jurassic

VI.	Mass Extinction's
	A.  Late Ordovician:  Global Cooling Event due to Gondwanaland Ice Caps
	    1.  Phase One Victims:  Planktic organisms (graptolites) and benthic organisms
	    (trilobites and brachiopods)
	    2.  Phase Two Victims:  Surviving trilobites; great reduction in numbers of 
	    corals, conodonts, bryozoans
	    3.  Specific effects of glaciation
		a.  cooling at higher latitudes
		b.  sea level lowered
		c.  loss of epeiric seas and shallow shelf areas
	B.  Late Devonian:  Global cooling due to Gonwanaland glaciation
	    1.  Occurred over 20 million years (not catastrophic)
	    2.  Eutrophication:  Probable cause of ecologic crisis
	    3.  Nearly eliminated:  Reef-building tabulate corals and stromatoporoids
	    4.  Most species extinguished:  Rugose corals
	    5.  Severely reduced numbers:  Brachiopods, goniatites, trilobites, conodonts,
	    placoderms
	C.  Late Permian ("Mother of Mass Extinction's")
	    1.  More than 90% of all marine species disappeared or were severely reduced
	    2.  Continental effects:  Spore bearing plants supplanted by conifers, cycads, 
	    sinkgoes, gymnosperms
	    3.  Disappeared:  Families of amphibians, primitive reptiles, mammal-like
	    reptiles
	    4.  Ecologic Chain Reaction:  Collapse of food chain likely
	    5.  Marine extinction's:  Rusulinids, rugose corals, many crinoids, productid
	    brachiopods, lacy bryozoans, many ammonoids
	    6.  Causes
		a.  Pangaea assembly
		b.  rigorous climatic conditions
		c.  drained epeiric seas
		d.  two frigid polar regions
		e.  equatorial circulation changes in ocean
		f.  extraordinary volcanic activity
		g.  flood basalt eruptions
		h.  greenhouse gas (CO2) effects