Paleozoic Life Life forms in the Paleozoic

Paleozoic Life

Life 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 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 morphology Arthropod – “jointed-leg” Related to Horseshoe crabs What other arthropods do you know of? Varied niche, predators, scavengers or filter feeders. Some swam, feeding on plankton

Brachiopod morphology Sessile benthic filter feeders related to bryozoans

Articulate Brachiopods Brachiopod 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 Inarticulate Brachiopod Lingula Infaunal sessile benthic filter feeders intertidal

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

Gastropod (snail) shapes

Cephalopod shell morphology

Crinoid morphology Stalked echinoderm related to starfishes, sea urchins, etc

Graptolites Related to ? ? ? Often found in black shales, deep shelf waters, no other fossils Great index fossils

What was the Cambrian Explosion? • 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 Shelly 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 fauna Photos A. Mollusk B. Sponge Drawings Late Proterozoic (Ediacaran) to Early Cambria, before trilobites.

Cambrian Marine Community • Many body plans are observed in Cambrian fossils, more than in any other period – trilobites – many niches, e. g. benthonic mobile sedimentdeposit feeders that crawled or swam across the sea floor – brachiopods - primitive benthonic sessile suspension feeders – archaeocyathids - benthonic sessile suspension feeders and reef builders

Invertebrates with hard parts Brachiopods Note how the valves have symmetry Trilobites Crinoids Sponges

The 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

Anomalocaris A huge predaor Hallucigenia Pikaia A chordate!!! Sidneyia Remarkable preservation of animals’ soft tissues, plus the first predator, Anomalocaris

Modern Brine Shrimp Artemia salina Similar swimming mode to Anomalocaris? Anomalocaris A huge predaor

Marella, a trilobitomorph or “Lace Crab” Anomalocaris and some known prey. Bite marks on fossils

Leanchoilia--China Leanchoilia--Burgess

Opabina

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

Pikaia 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 Pikaia – an early chordate! from the Burgess Shale

Cambrian Trilobites Paradoxides bohemicus Barrande YPM 72949 Cambrian, Etage C. Koneprussy, Bohemia, Czechoslovakia.

Archaeocyathids (sponges? )

Ordovician Marine Community Note large Orthoceras A Cephalopod Mollusk • 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 sealevel Cephalopods as Index Fossils

Bryozoans Possibly related to Brachiopods • “Moss Animals” • Filter Feeders • Mostly marine tropical • Make hard exoskeleton, chitin or Ca. CO 3 •

Bryozoans In fossils, just the exoskeleton is preserved

Halysites Tabulate Coral O-S

Stromatoporoid - Hydrozoan coral or Sponge? - - K C

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 Grounds & 0. 1 S 54 W of Marathon, Brewster Co. , Texas, USA. Collector: Berry, W. B. Graptolite

Silurian and Devonian Marine Communities • 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 Pterygotus Marine “Scorpions” Track ways in coastal sands Probably laid eggs as horseshoe crabs do along the foreshore

Rugose Corals – individual animals Field Trip, Stroudsburg, PA

Devonian Tabulate Corals Favosites conicus Hall YPM 7115 Early Devonian, Oriskany Sandstone. Loc. C 6644, Cumberland, Allegany Co. , Maryland, USA Collector: Gordon, R. H. & Hartley, F. Colonial

Brachiopod 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.

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

Carboniferous and Permian Marine 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 Cystoids Anomalocystis cornutus Hall YPM 36413 Early Devonian, Helderberg Grp. Lower Helderberg, Jerusalem Hill, Herkimer Co. , New York, USA.

Types of Staked Echinoderms 2 Blastoids Pentremites sulcatus YPM 36130 Pennsylvanian, Gaptank Fm. Unit 7 (27 ft thick), Section 32, 1. 25 mi S 60 W 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. Fragments on Field Trip Stroudsburg PA Types of Staked Echinoderms 3 - Crinoids Types of Staked Echinoderms

Vertebrate 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 subphylum 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

Fish • 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 time

Ostracoderms- Jawless fish Field Trip Bony plates in Shf Silurian High Falls at Delaware Water Gap

Evolution of jaws

Placoderms – first fish w jaws Dunkleosteous (Dinichthys) a Devonian arthrodire

Placoderm - 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 Placoderm a more usual body plan Climatius, a Lower Devonian acanthodian

Cartilagenous fishes: Fossil Shark http: //www. exhibits. lsa. umich. edu/New/Welcome. html Cladoselache fyleri, a 3 -foot shark, was one of the top predators in the Devonian seas.

Bony Fishes (Osteichthys) Ray-finned (Actinopterygians) and Lobe-finned (Sarcopterygians)

Rhipidistian fish (Crossopterigian) Field Trip Catskill fm. Bones of early Amphibians Similar skulls, teeth, Bones in limbs. Fish limbs not for walking

Hyneria lindae from Hyner, PA http: //www. lhup. edu/jway/rdhll/Red. Hill. htm

Amphibians Vertebrates 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 Amphibian Late Devonian Ichthyostega Skull, teeth, backbone and tail are Rhiphidistian-like

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

Middle Carboniferous - Evolution of the Reptiles The 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 • 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 Warm Cool

Skull structure in reptiles, temporalis muscle Eury wide An not, without Syn united, together Dia double Early Therapsids Function of Temporal Openings

Pelycosaurs herbivorous Edaphosaurus Discussion: Sail function Thermoregulation Armor Courtship carnivorous Dimetrodon

Evolution 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 therapsids

Back to the early Paleozoic to consider plant evolution Land 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

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

Lepidodendron L Dev. – Penn. A lycopod tree 90 – 100 feet tall An important coal-former

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

Spenopsid (Horsetail Rush) Calamites shown L. Dev – E. Penns. Floras Lycopsid (club moss) Lepidodendron shown • Source of coal • Seedless vascular: Need moisture to reproduce, vulnerable to insect attack – Lycopsids to 30 m branches at top; leaves similar to palm – Sphenopsids jointed stem underground rhizomes • First Seed Ferns Late Devonian West Virginia seed ferns

L. Pennsylvanian – M. Permian Floras • 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 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 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 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 d 13 C at the boundary had a duration of 165, 000 years or less, suggesting a catastrophic addition of light carbon. GLOBAL FIRE!

d 13 C • 12 C and 13 C are stable isotopes of Carbon 12 C 98. 89% 13 C 1. 11% in today’s atmosphere Negative excursions mean 13 C down or 12 C up.

d 13 C • 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 aligned Extinction

Major mass-extinction events Asteroid Impact Supposedly due to glaciation but it doesn’t line up with low water Mention 26 -30 my cycle of extinctions