Transcript Paleozoic Life Vertebrates & Plants

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
fish
Anatolepis piece, Jawless
U. Cambrian
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
– L. Silurian
– Extinct Permian
• Major Advancement
Placoderms
– 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
– Thin bone spread from body
– Fresh-H2O beginning
– Trout, bass
• Lobe finned
– Muscular fins; no radiating fins
– Articulating bones
– 2 types of lobe-finned
Paleozoic Vertebrate
2 Types of Lobe-Finned
• Lobe-Finned Types
– Lung Fish
 Lungs evolved from sac-like
bodies
 Adapted for H2O variations
Lung fish
– Crossopterygians
 Most important
 Amphibian evolution
Rhipidistian
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
– 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
Recent gelatinous egg
– No need to return to H2O
Paleozoic Vertebrates
Reptiles
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
Pennsylvanian reptile, Hylonomus
Evolution
•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