Paleozoic Life Vertebrates & Plants

Paleozoic Vertebrate Introduction Vertebrate evolution Fish  amphibian  reptile Transition from H2O to land Plants preceded animals Method of reproduction Evolution of the seed = plants Amniote egg = animals Time of major extinctions (end of Paleozoic Era) Marine invertebrates Many amphibians and reptiles

Paleozoic Vertebrate Fish Evolution Ancestors Similar to amphibians May have evolved from sessile suspension feeders Class Agnatha – Jawless fish Class Acanthodians – 1st Jawed fish

Paleozoic Vertebrate Fish Evolution Most primitive vertebrate -- fish Oldest fish  Upper Cambrian Phosphatic; Jawless fish, class Agnatha Shallow near-shore marine deposits Earliest non-marine  Silurian Ostracoderm Anatolepis piece, U. Cambrian Jawless fish

Paleozoic Vertebrate Devonian Seafloor

Paleozoic Vertebrate Evolution of Jaws “Evolutionary Opportunism” Early jaws for respiration Open mouth wider; more O2 Led to ↑ food consumption Class Acanthodians Placoderms L. Silurian Extinct Permian Major Advancement Active predators Eat plants New niches

Paleozoic Vertebrate Late Devonian Seafloor

Paleozoic Vertebrate Cartilaginous & Bony Fish Class Chondrichthyes (cartilaginous) Devonian Related to sharks, rays, skates Primitive sharks – L. Devonian Class Osteichthyes (bony fish) Devonian Two groups Ray finned Lobe finned

Paleozoic Vertebrate Bony Fish Ray finned Lobe finned Thin bone spread from body Muscular fins; no radiating fins Fresh-H2O beginning Articulating bones 2 types of lobe-finned Trout, bass

Paleozoic Vertebrate 2 Types of Lobe-Finned Lung fish Lobe-Finned Types Lung Fish Lungs evolved from sac-like bodies Adapted for H2O variations Rhipidistian Crossopterygians Most important Amphibian evolution

Paleozoic Vertebrate Lobe-finned & Amphibian Similarities

Paleozoic Vertebrate Amphibians 1st Vertebrates on land – L. Devonian Plants 1st land organisms Spiders and insects before vertebrates Crossopterygians

Paleozoic Vertebrate Transition from H2O to Land Major Barriers Dessication Reproduction (need H2O) Effects of gravity Extraction of O2 from atmos. Crossopterygians overcame Barriers Backbone Limbs Lungs Amphibians exploit new niches

Paleozoic Vertebrate Evolution of Reptiles Amphibians limited to colonizing land Recent gelatinous egg Gelatinous egg laid in H2O Amniote egg Embryo surrounded by liquid “Anion” provided yolk (food sac) Miniature adult Bypass larval stage Led to colonization all parts of land No need to return to H2O

Paleozoic Vertebrates Reptiles Pennsylvanian reptile, Hylonomus Evolution Reptiles evolve in Late Mississippian Protorothyrids = earliest reptiles Diversified in Permian—displaced amphibians—more successful Pelycosaurs evolve from protorothyrids Extinct in Permian Pelycosaurs succeeded by therapsids Mammal-like reptile Both carniverous and herbivorous Endothermic—warm-bloooded Could occupy both cold and warm niches—high and low latitudes 2/3 reptiles and aphibians extinct at close of Permian.

Paleozoic Vertebrate Plant Evolution Marine  fresh H2O  land Problems to solve Dessication Support Effects of gravity Reproduction (needs H2O) Vascular (seedless) Earliest  middle Silurian Specialized cells Movement of H2O Non-Vascular Earliest plants mid-late Ord No specialized cells Live in low, moist areas

Paleozoic Vertebrate Seed Evolution Gymnosperms (flowerless seed plants) Late Devonian Male and female cones Seed plants no longer restricted to wet areas

Paleozoic Vertebrate Permian Floras Major source of world’s coal Results from alteration of plants living in low, swampy areas