Introduction 1 Early Mesozoic a Late Permian ME i Very few organisms survived the major ii At first recovery of life was slow b Biota i Gymnosperms dominate ii Age of the dinosaurs begins c Geology i Pangaea forms ii Pangaea rifts d Global eustatic transgression 2 Triassic Period a Fully assembled Pangaea i Fairly dry climate b Growth of western NA c Late Triassic i Mollusks became diverse ii Hexacorals appeared modern reef builders iii Marine reptiles swimming predators iv Seeds and seed ferns abundant v 1st turtles vi 1st flying reptiles vii 1st dinosaurs viii 1st mammals d Pangaea starts to fragment late Triassic e End Triassic ME 3 Jurassic Period a Pangaea rifting b Rapid sea level rise i Extensive record of marine deposition 1 Dinoflagellates and calcareous nannoplankton appear 2 Large reefs form i One of three types dominating early Mesozoic forests c Continued growth of western NA d Age of the Cycads e Dinosaurs rise to dominance i Therapsids disappear f 1st birds appear Marine Biota 1 End Permian ME a Fusulinid foraminifera b Lacy brozoans c Rugose corals d Trilobites 2 Brief return of stromatolites and thrombolites 3 Benthic life a Mollusks b Ammonoids i Bivalves became most abundant and diversified ii Brachiopods i 2 surviving genera diversified to 100 in Triassic c Sea urchins d Reef recovery initiated with sponges and algae e Hexacorals i New benthic species ii Replaced the sponge and algae coral builders iii Modern framework builders 4 Pelagic life a 2 new groups of photosynthesizing phytoplankton b Evolved from earlier acritarch ancestors i Dinoflagellates 1 Unicellular algae protists 2 Zooxanthellae a Linked to coral success ii Calcareous nannoplankton 1 Unicellular algae protists 2 CaCO3 skeletons c Swimming nektonic predators i Ammonoids 1 Swimming predators 2 ii Belemnoids Important index fossils of Meso 1 Marine mollusks 2 Similar to squid like relatives of ammonoids 3 iii Conodonts Jet propulsion 1 Fish like vertebrates 2 Very common in Triassic a Known since Cambrian but useful for correlating Triassic 3 Disappear by Jurassic end Triassic ME d Ray fin fish i Diamond shaped scales not quite overlapping ii Development of swim bladder iii Peg like teeth to crush shell fish e Sharks i Well represented in early Meso ii Teeth adapted for crushing shellfish iii Several modern shark groups first appeared f Marine reptiles appeared Sea monsters model for movies i ii 1st were nothosaurs 1 Paddle like limbs 2 Like seals may have periodically lived on shore iii Placodonts iv Plesiosaurs v Ichthyosaur 1 Blunt toothed shell crushers 1 Evolved from nothosaurs 2 Spike shaped teeth wing like limbs 1 Fish like reptile 2 Resembled dolphins 3 Up to 20 m length vi Early crocs 1 Last group of Meso marine reptiles to evolve a Terrestrial marine 2 Had fine like tail Life on Land 1 Gymnosperms dominated early Meso flora a Permian ME quickened the decline of spore plants b Gymnosperms thin rise to abundance i At fist lycopods and ferns dominated ii Trees were mostly gymnosperms 1 Cycads and cycadeoids 2 Conifers 3 Ginkgos 2 Cycad and sycadeoids a Look similar to palms b Meso Age of Cycads 3 Conifers a All but pine present b Adapted to dry cool climates 4 Ginkgos a Similar to conifers b Shed their leaves annually 5 Age of the Dinosaurs begins late Triassic a Evolved from dinosauromorphs i A reptile group that evolved in the early Triassic ii Most walked on fours iii Some walked ran on two iv Legs extended straight downward beneath their bodies b 1st dinosaurs Dinosauria i Traveled on 2 hind legs ii Different skulls iii Highly developed teeth iv Initially small c Dinosauria 2 sub groups i Ornithischia ii Saurischia 1 Bird hipped pelvis 2 Herbivores 3 Bi or quadrepedal 1 Lizard hipped pelvis 2 Herb carnivores 3 Bi or quadrepedal d Sauropods lizard hipped were the largest of all dinosaurs i Quadropedal ii Great success likely due to high level of metabolism e Morrison Formation Montana to NM reveals fauna including many sauropods as well as other dinosaurs 6 Frogs and turtles a 1st became established in the Triassic b Frogs i Amphibians ii Small c Turtles 7 Pterosaur reptiles take to the air in late Triassic a Long wings b Hollow bones like birds today c Some had long tails d Hook like claws 8 Birds evolved from dinosaurs in late Jurassic i Reptiles ii Earliest lacked ability to pull their heads and tails into shells a First discovered from a fossil feather 1861 b Bird found a few months later Archaeopteryx ancient wings c Similar to small dinos but with plumage d Missing link for dinos to birds i Teeth tail clawed forelimbs from dino full blown feathers a 9 Therapsids bird a Only a few survived terminal Permian ME b Re diversified and played important role in Triassic c Barely survived into Jurassic 10 Mammals evolve from therapsids near late Triassic 11 Late Triassic many organisms present a Amphibians b Reptiles c Therapsids d Dinosauromorphs e dinosaurs