Life in the Paleozoic Ocean Planet & The Great Migration Paleozoic Late Middle Early 543-248 Myr P r e c a m b r i a n Eon P h a n e r o z o i c Proterozoic Archean Hadean Geologic Time Scale Era Period Age (Myrs) Epoch Holocene 0.01 Quaternary C 1.8 Pleistocene e Pliocene n 5.3 Neogene o Miocene z 23.8 o Tertiary i 33.6 Oligocene c Paleocene 54.8 Eocene 65 Paleocene M e Cretaceous s 144 o Jurassic z 206 o i Triassic c 248 P a Permian Pennsylvanian 290 323 l Mississippian e o Devonian z 354 417 o i Silurian 443 c Ordivician Cambrian 490 543 Age of the Earth 4600 Myrs (4.6 Byrs) Source: Geological Society of America (1999) 2500 3800
Vertebrate Evolution From Pikaia to Cheney Phylum Chordata Including Subphylum Vertebrata 1. Notochord 2. Nerve cord 3. Pharyngeal gill slits Vertebrates Vertebral column replaces notochord & skull encloses brain
Phylogeny Reminder Fish --> Amphibians --> Reptiles --> Mammals Think in terms of common ancestors and speciation
Fish Phylogeny Cephalasphid Fish: Jawless Fish (Agnatha) Early Paleozoic ostracoderms. (A) Thelodus, (B) Pteraspis, (C) Jamoytius, and (D) Hemicyclaspis, drawn to the same scale.
Modern Agnatha: Sea Lamprey Origin of Jaws
Fish: Armored Fish (Placoderms) Dunkleosteus Bothriolepis Extinct Fish: Armored Fish (Acanthodians) Armor - a form of phosphorus storage? Extinct Acanthodes
Fish: Chondrichthyes (Cartilaginous Fish) Modern Chondrichthyes (Sharks & Rays)
Fish: Osteichthyes (Bony Fish) Osteichthyes: Ray Fined Subclass: Actinopterygii Rays
Ray Finned Fish Sturgeon Longnose Gar Ray Finned Fish: Teleosts Weedy Sea Dragon 96% of today s fish Zebrafish
Osteichthyes: Lobe Finned Subclass: Sarcopterygii Lobe Finned Fish Coelacanth
Lobe Finned Fish Lungfish Eusthenopteron
The Great Migration (Silurian/Devonian) Plants, Insects, Vertebrates (Tetrapods) Amphibians
Amphibians Wood Frog Eggs Lobe Fins to Amphibians
Acanthostega (Upper Devonian) Ichthyostega (Upper Devonian)
Advantages to Moving onto Land 1. Lots of light for photosynthesis 2. Easy access to oxygen and carbon dioxide 3. Less competition 4. Rich source of nutrients an (eventually) food 5. Fewer predators Challenges to Moving onto Land 1. Conserving water - not drying out 2. Obtaining & circulating water, food & gases 3. Overcoming gravity 4. Reproduction 5. Exposure to UV
Vertebrate Solutions 1. Conserving water - not drying out Leathery skin & scales 2. Obtaining & circulating water, food & gases 3 or 4 chambered heart 3. Overcoming gravity Modified skeletal arrangement 4. Reproduction Internal Fertilization & Amniotic Egg 5. Exposure to UV Leathery skin & scales Encloses embryo in water Regulates oxygen.carbon dioxide exchange Amniotic Egg Collects wastes Food = Freedom from Oceans
Permian Reptile Egg Modern Reptile Skin
The Amniotes Diapsids (Includes lizards, dinosaurs & birds)) Classified based on skull structure Synapsids (Includes mammals) Anapsids (Includes turtles) Amniote Cladogram About 300 Myr
Anapsids & Diapsids (True Reptiles) Early Permian - Labidosaurus Anapsids & Diapsids (True Reptiles)
Early Synapsids (Mammal-Like Reptiles) Pelycosaurs (Sail Fins) Temperature control? Dimetrodon
Therapsids (Permian Synapsids) Dicynodonts Cynodont More on Synapsid, Mammal, and Reptile Evolution in the Mesozoic
Paleozoic Plant Evolution First Forays: Intertidal Marine Algae
Problems with Moving to Land 1. Conserving water - not drying out 2. Obtaining & circulating water, food & gases 3. Overcoming gravity 4. Reproduction Sunlight above ground Nutrients below ground 5. Exposure to UV Plant Solutions to Dry Living 1. Conserving water - not drying out Developed waxy coating 2. Obtaining & circulating water, food & gases Vascular tissue and roots, and pores 3. Overcoming gravity Thicker cells - wood/cellulose 4. Reproduction First spores, then pollen, seeds, & flowers 5. Exposure to UV Pigments
First Colonists: Bryophytes No Plumbing System - small low to the ground Early Plants: 1. Stabilized soil - reduced erosion 2. Began the process of creating soil 3. Provided food for animals to move to land
Vascular Plants Rhynia Plumbing and woody material allowed for increase in size Vascular Plant Evolution
First Plants Reproduced Using Spores (Still required water) Horsetails (Calamites) Annularia stellata
Ferns Pecopteris sp. Clubmoses: Lepidodendron
Miss/Penn Forests (Ferns, Horsetails & Clubmoss) Illustration by Mary Parrish Gymnosperms Pollen (male) Seed Cone (Female)
Seed Ferns Neuropteris sp. Ginkos
Angiosperms Conifers
The Not-So-Naked Seed Fossil Leaves and Flowers
Plant Summary 1. Paleozoic - Plants move to land - Dominated by bryophytes & seedless vascular Plants 2. Mesozoic - Dominated by gymnosperms - Angiosperms arise 3. Cenozoic - Dominated by angiosperms First in Flight - Pennsylvanian Cretaceous dragonfly
Meganeura monyi (roughly to scale) The largest insect in history More to come in the Mesozoic