Paleozoic LifePaleozoic Life

Life forms in the PaleozoicLife forms in the Paleozoic• The paleozoic begins with the appearance of fossils of

marine animals. For the first time, ocean animals that have easily fossilized hard parts.

• The paleozoic contains the history of animal and plant diversification in the oceans and colonization of land

Crinoids

Important Paleozoic InvertebratesImportant Paleozoic Invertebrates

• First we will examine the anatomical plans of Trilobites, Brachiopods, Molluscs (clams, snails and cephalopods), Echinoderms (starfish, sea urchins and especially crinoids), and Graptolites.

• Later we will look at corals and sponges

Trilobite shell morphologyTrilobite shell morphologyArthropod – “jointed-leg”

Related to Horseshoe crabsWhat other arthropods do you know of?

Varied niche, predators, scavengers or filter feeders. Some swam, feeding on plankton

Brachiopod morphologyBrachiopod morphology

Sessile benthic filter feeders related to bryozoans

Articulate BrachiopodsArticulate BrachiopodsBrachiopod life positions 1Brachiopod life positions 1

Brachiopods sort of look like a clam. However, notice that each valve is symmetrical about its middle line.

Brachiopod life positions 2 Brachiopod life positions 2 Inarticulate Brachiopod Inarticulate Brachiopod

Lingula Infaunal sessile benthic filter feeders intertidal

Bivalve morphologyBivalve morphology

Clams, Scallops Individual valve is not symmetrical about a middle line

Gastropod (snail) shapesGastropod (snail) shapes

Cephalopod shell morphologyCephalopod shell morphology

Crinoid morphologyCrinoid morphology

Stalked Stalked echinoderm echinoderm related to related to

starfishes, sea starfishes, sea urchins, etcurchins, etc

GraptolitesGraptolitesRelated to ??? Often found in black shales, deep shelf waters, no other fossils

Great index fossils

What was the What was the Cambrian Cambrian ExplosionExplosion??

• The Paleozoic is marked by the abrupt appearance of animals with skeletons in the rock record– a mechanism that would trigger this event is not

agreed upon, but is surely due to a combination of geologic and biologic factors

– Predators prominent – shallow water, animals must be protected from UV.

The Emergence of The Emergence of Shelly FaunaShelly Fauna

• Organisms with hard parts have many advantages– protection against UV rays, allowing animals to

move into shallower water– helps prevent drying out in an intertidal environment– provides protection against predators

Small shelly faunaSmall shelly faunaPhotos

Drawings

Late Proterozoic (Ediacaran) to Early Cambria, before trilobites.

A. Mollusk B. Sponge

Cambrian Marine CommunityCambrian Marine Community

• Many body plans are observed in Cambrian fossils, more than in any other period– trilobites – many niches, e.g. benthonic mobile sediment-

deposit feeders that crawled or swam across the sea floor– brachiopods - primitive benthonic sessile suspension feeders– archaeocyathids - benthonic sessile suspension feeders and

reef builders

Trilobites

Sponges

BrachiopodsNote how the valves have symmetry

Crinoids

Invertebrates with hard parts

The Burgess Shale BiotaThe Burgess Shale Biota• Consists of a rare preservation of soft-bodied organisms – Mid Cambrian

– Some phyla near the basic stock from which some present-day invertebrates have evolved

– Other unique and without issue– current debate centers around how many phyla arose and how many extinction

events took place in the Cambrian

Charles Walcott’s Burgess Shale

-middle Cambrian shale in the Rockies of western Canada

PikaiaA chordate!!! Sidneyia

Hallucigenia

AnomalocarisA huge predaor

Remarkable preservation of animals’ soft tissues, plus the first predator, Anomalocaris

Modern Brine Shrimp Modern Brine Shrimp Artemia salinaArtemia salinaSimilar swimming mode to Anomalocaris?

AnomalocarisA huge predaor

Anomalocaris and some known prey.Bite marks on fossils

Marella, a trilobitomorphor “Lace Crab”

Leanchoilia--China

Leanchoilia--Burgess

Opabina

Interpreting Interpreting HallucigeniaHallucigenia

Like the modern Peripatus, moist forests of Cameroon, Discussion: preadaptations to land if food is present

PikaiaPikaia

Pikaia – an early chordate! from the Burgess Shale

Totally unexpected find. Cartilage but no bone.Jawless ancestor to fish, and us.Maori legend of Pikea, the ancestor.Lancelets in comparative anatomy

Link to lancelet info

                       

       

Paradoxides bohemicus Barrande

YPM 72949 Cambrian, Etage C. Koneprussy, Bohemia, Czechoslovakia.

Cambrian Trilobites

Archaeocyathids (sponges?)Archaeocyathids (sponges?)

Ordovician Marine CommunityOrdovician Marine Community• Vast epeiric seas

opened new marine habitats– bryozoans,

stromatoporoids, tabulate and rugose coral reef builders

– reefs with high diversity - suspension feeders

– massive extinctions end Ordovician, glaciation in Gondwana & falling sea-level

Note large OrthocerasA Cephalopod Mollusk

Cephalopods as Index Fossils

BryozoansBryozoans• Possibly related to Brachiopods

•“Moss Animals”

•Filter Feeders

•Mostly marine tropical

•Make hard exoskeleton, chitin or CaCO3

BryozoansBryozoans

In fossils, just the exoskeleton is preserved

Halysites Tabulate Coral O-SHalysites Tabulate Coral O-S

Stromatoporoid - Hydrozoan coral Stromatoporoid - Hydrozoan coral or Sponge? or Sponge? CC - K - K-

                 

                            

http://www.yale.edu/ypmip/Didymograptus denticulatus Berry

YPM 20252 Early Ordovician, Marathon Ls. Didymograptus bifidus zone, upper Marathon, 14.5 ft below Marathon top, section XVIII, bed of Alsate Creek, 3 mi W of Picnic Picnic Grounds & 0.1 S54W of Marathon, Brewster Co., Texas, USA. Collector: Berry, W.B.

Graptolite

Silurian and Devonian Marine Silurian and Devonian Marine CommunitiesCommunities

• Rapid diversification and recovery followed the Ordovician mass extinction– reef building by tabulate and

rugose corals– NEW PREDATOR :

Eurypterids were abundant

– Ammonoids evolved quickly and are important as index fossils

– mass extinction at the end of the Devonian collapsed the massive reefs

Marine “Scorpions”Track ways in coastal sandsProbably laid eggs as horseshoe crabs doalong the foreshore

Pterygotus

Rugose Corals – individual animalsRugose Corals – individual animals

Field Trip, Stroudsburg, PA

Devonian Tabulate CoralsDevonian Tabulate Corals

          

                           

Favosites conicus Hall YPM 7115 Early Devonian, Oriskany Sandstone. Loc. C6644, Cumberland, Allegany Co., Maryland, USA. Collector: Gordon, R.H. & Hartley, F.

Colonial

                           

                  

Leptaena rhomboidalis (Wilkens) YPM 19154 Early Devonian, Helderberg Grp, New Scotland Ls. Lower Helderberg, Indian Ladder, Thatcher State Park, near New Salem, Albany Co., New York, USA. Collector: Beecher, C.E.

Brachiopod

   

                             

Phacops rana (Green)

YPM 6593 Middle Devonian, Hamilton Grp. Eighteen Mile Creek, Erie Co., New York, USA. Collector: Beecher, C.E.

Carboniferous and Permian Carboniferous and Permian Marine CommunitiesMarine Communities

• Renewed diversity and recovery with adaptations mark the Late Paleozoic marine communities– bryozoans and crinoids

reach their greatest diversity

– patch reefs replace the massive reefs of the Devonian –TEMPS?

– fusulinid formanifera are important index fossils

Types of Staked Echinoderms 1 Types of Staked Echinoderms 1 CystoidsCystoids

      

                                       

Anomalocystis cornutus Hall YPM 36413 Early Devonian, Helderberg Grp. Lower Helderberg, Jerusalem Hill, Herkimer Co., New York, USA.

Types of Staked Echinoderms 2 Types of Staked Echinoderms 2 BlastoidsBlastoids

          

                                   

Pentremites sulcatus

YPM 36130 Pennsylvanian, Gaptank Fm. Unit 7 (27 ft thick), Section 32, 1.25 mi S60W of the Brooks Ranch House, Glass Mountains, Pecos Co., Texas, USA. Collector: Ross, C.A.

                 

                                     

Barycrinus hoveyi (Hall) YPM 34788 Early Mississippian, Edwardsville Fm. Crawfordsville, Montgomery Co., Indiana, USA. Collector: Bassett, D.A. 1888.

Types of Staked EchinodermsTypes of Staked Echinoderms 3 - Crinoids

Fragments on Field TripStroudsburg PA

Vertebrate EvolutionVertebrate Evolution• Chordates have, during at least part of their

life, a notochord, dorsal hollow nerve chord, and gill slits– Vertebrates have backbones and are a sub-

phylum of chordates– ancestors were soft-bodied and left few fossils– a close relationship exists between echinoderms

and chordates and they may have shared a common ancestor

FishFish• Fish range from the Late Cambrian to

the present and consist of five classes• Ostracoderms• Placoderms• Acanthodians • Cartilaginous fish – sharks and rays• Bony fish

Classes of fish through timeClasses of fish through time

Ostracoderms- Jawless fishOstracoderms- Jawless fishField TripBony plates in Shf Silurian High Falls at Delaware Water Gap

Evolution of jawsEvolution of jaws

Placoderms – first fish w jawsPlacoderms – first fish w jawsDunkleosteous (Dinichthys) a Devonian arthrodire

PlacodermPlacoderm - Bothryolepis - Bothryolepis

• Today we will examine another Placoderm

• Named Bothryolepis

• It’s armor is similar to that of modern South American catfishes that live in shallow, fast moving, jungle streams in South America

Acanthodian PlacodermAcanthodian Placoderm a more usual body plana more usual body plan

Climatius, a Lower Devonian acanthodian

Cladoselache Cladoselache fylerifyleri, a 3-foot , a 3-foot

shark, was one shark, was one of the top of the top

predators in the predators in the

Devonian seas.Devonian seas.

Cartilagenous fishes: Fossil SharkCartilagenous fishes: Fossil Sharkhttp://www.exhibits.lsa.umich.edu/New/Welcome.html

Ray-finned (Actinopterygians) and Lobe-finned (Sarcopterygians)Ray-finned (Actinopterygians) and Lobe-finned (Sarcopterygians)

Bony Fishes (Osteichthys)

Rhipidistian fishRhipidistian fish

(Crossopterigian)

Similar skulls, teeth,Bones in limbs.

Fish limbs not for walking

Field Trip Catskill fm.Bones of early Amphibians

Hyneria lindaeHyneria lindae from Hyner, PA from Hyner, PAhttp://www.lhup.edu/jway/rdhll/RedHill.htm

Amphibians -Amphibians -Vertebrates Invade the LandVertebrates Invade the Land

• The first vertebrates to live on land, preceded by plants, insects, and snails

• Barriers they had to deal with:– desiccation

– reproduction

– effects of gravity

– extraction of oxygen by lungs rather than gills

Early AmphibianEarly Amphibian

Late Devonian IchthyostegaSkull, teeth, backbone and tail are Rhiphidistian-like

Labyrinthodont amphibianLabyrinthodont amphibian

Eryops, a carnivorous amphibian, named for folds in teeth Pennsylvania to Early Permian

Middle Carboniferous - Evolution of Middle Carboniferous - Evolution of the Reptiles the Reptiles

The Land is ConqueredThe Land is Conquered• The evolution of the

amniote egg freed reptiles from the constraint of returning to water to reproduce– amnion - liquid filled sac

surrounding the embryo

– allantois - waste sac

– a tough shell protects the developing fetus

– reptiles were able to colonize all parts of the land

Evolution of the Reptiles Evolution of the Reptiles

• The earliest reptiles are from the Lower Pennsylvanian– called Captorhinomorphs,

they were small, agile, and probably fed on insects

– success due to advanced egg, more advanced jaws and teeth, and speed

– Later reptiles evolved from this group by Permian

Cool

Warm

Skull structure in reptiles, temporalis muscleSkull structure in reptiles, temporalis muscle

Early Therapsids

Function of Temporal Openings

Eury wideAn not, withoutSyn united, togetherDia double

PelycosaursPelycosaurs

herbivorous Edaphosaurus

carnivorous Dimetrodon

Discussion: Sail function

Thermoregulation

Armor

Courtship

Evolution of the ReptilesEvolution of the Reptiles• Therapsids succeeded the pelycosaurs during the

Permian– mammal-like reptiles that quickly evolved into herbivorous

and carnivorous forms– they displayed fewer bones in the skull, enlargement of the

lower jawbone, differentiation of the teeth, and a more vertical position of their legs

– therapsids may have been endothermic, which may help explain their distribution over wide latitudes

• End Permian extinction eliminated about 66% of all amphibians and reptiles

Late Permian therapsidsLate Permian therapsids

Land Plant Evolution - SilurianLand Plant Evolution - Silurian• Plants had the same water-to-land transition

problems that animals did– vascular land plants have a tissue system to move water– nonvascular plants do not have this system, and are usually

small and live in moist environments– seedless vascular plants such as ferns closely resemble

green algae in their pigmentation, metabolism, and reproductive cycle

– green algae have also been able to make the transition from salt water to fresh water, leading some to believe that modern terrestrial land plants evolved from them

Back to the early Paleozoic to consider plant evolution

Silurian and Devonian FlorasSilurian and Devonian Floras• The earliest land plants earliest land plants are from the Silurian

– small, simple leafless stalks with a spore-producing structure at the tip (Rhynia drawing and modern Psilotum pictured)

– a rhizome (the underground part of the stem) transferred water from the soil to the plant and anchored it

– leaves, roots, and secondary growth all followed during the Devonian

• The evolution of the first seed allowed land plants (“Seed Ferns”) to spread over all parts of the land

LepidodendronLepidodendron L Dev. – P L Dev. – Penn.enn.A lycopod tree 90 – 100 feet tallA lycopod tree 90 – 100 feet tall

An important coal-former

Calamites,Calamites, a huge horsetail rush a huge horsetail rush 10-14 meters tall (Pennsylvanian)10-14 meters tall (Pennsylvanian)

L. Dev – E. Penns. FlorasL. Dev – E. Penns. Floras

• Source of coal• Seedless vascular: Need

moisture to reproduce, vulnerable to insect attack

– Lycopsids to 30m branches at top; leaves similar to palm

– Sphenopsids jointed stem underground rhizomes

• First Seed Ferns Late Devonian West Virginia

seed ferns

Spenopsid (Horsetail Rush) Calamites shown

Lycopsid (club moss) Lepidodendron shown

L. Pennsylvanian – M. Permian L. Pennsylvanian – M. Permian FlorasFloras

• Seed-bearing vascular– Gymnosperm trees -

Cordaites, Glossopteris, and others were able to colonize large areas of land

– many of these became extinct in the Late Permian; those that survived were able to tolerate the warmer and drier climates

Insects and other land arthropodsInsects and other land arthropods

• Have a strong exoskeleton, impervious to water so good for osmoregulation.

• Predation on plant spores probably a strong selective pressure for seed coatings.

          

                                   

Petalia sp. YPM 29867 Late Jurassic, Kimmeridgian, Solnhofen Ls. Solnhofen, Bavaria, West Germany.

Permian Marine Extinction EventPermian Marine Extinction Event

• The greatest recorded mass extinction to affect Earth occurred at the end of the Permian– about 90% of all marine invertebrate species– fusulinids, rugose and tabulate corals, many bryozoan and

brachiopod orders, and trilobites did not survive the end of the Permian

– causes for this have been speculated to be:• reduction in marine shelf as Pangaea formed• global drop in sea level due to glaciation• reduction in marine shelf due to regression• climatic changes

Fusilinids, large forams

Permian Extinctions Permian Extinctions

S. A. Bowring, et. al. (1998) U/Pb Zircon Geochronology and Tempo of the End-Permian Mass Extinction. SCIENCE 280 :1039-1045

• The mass extinction at the end of the Permian was the most profound in the history of life.

• U/Pb zircon data from south China place the Permian-Triassic boundary at 251 mya.

• Strata intercalated with ash beds below the boundary: Changhsingian pulse of the end-Permian extinction (loss of 85 percent of marine species) lasted less than 1 my.

• At Meishan, a negative excursion in 13C at the boundary had a duration of 165,000 years or less, suggesting a catastrophic addition of light carbon. GLOBAL FIRE!

13C13C

• 12C and 13C are stable isotopes of Carbon12C 98.89% 13C 1.11% in today’s atmosphere

Negative excursions mean 13C down or 12C up.

13C13C• Standard carbon in calcite from belemnites Pee

Dee Formation (abbreviated as PDB).• The process of photosynthesis favors the lighter

form of carbon • “If you recall from the above brief discussion of

the soot found in the … clay layer, it appears that a significant portion of the land plants burned; this would have released a great deal of light carbon into the atmosphere”

Extinctions alignedExtinctions aligned

Extinction

Extinction

Extinction

Major mass-extinction eventsMajor mass-extinction events

Supposedly due to glaciationbut it doesn’t line up with low water

Asteroid Impact

Asteroid Impact

Asteroid Impact

Mention 26-30 my cycle of extinctions

Asteroid Impact