CHAPTER 13
PALEOZOIC LIFE: VERTEBRATES AND PLANTS
PALEOZOIC
ERA
CHAPTER
13: PALEOZOIC LIFE HISTORY: VERTEBRATES & PLANTS
CHAPTER
OUTLINE
CHAPTER
OUTLINE
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PLANT EVOLUTION
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INSECT EVOLUTION
INTRODUCTION
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Ch 12: invertebrate
evolution in Pz
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Ch 13: vertebrates &
plants
VERTEBRATE
EVOLUTION
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Chordate phylum:
animal w/ spinal nerve chord
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Vertebrates subphylum:
– Animals w/ backbones
– Ancestors: soft-bodied, few fossils
– 1st appearance: Cambrian
FISH
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Fishes: most primitive
vertebrates
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1st fishes:
– Class Agnatha (jawless fishes)
– Includes ostracoderms: bony-skinned jawless
fishes
– Cambrian-Devonian
FISH
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1st jawed
fishes:
– Acanthodians
– Predatory response to protective shells
– Silurian-Permian
FISH
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Plate-skinned placoderms:
primitive jawed fish w/ armor
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L. Silurian-Permian
FISH
FISH
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Cartilaginous fish
(Chrondrichthyes)
FISH
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Bony fish (Osteichthyes)
FISH
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Ray-finned:
– Limbs supported by thin bones that spread away fr.
body
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Lobe-finned:
– Fins have articulating bones & muscles; greater
flexibility
FISH
AMPHIBIANS-
VERTEBRATES INVADE THE LAND
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Land 1st
occupied by plants & insects
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Source of food
AMPHIBIANS-
VERTEBRATES INVADE THE LAND
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Extraction of O2:
– Lobe-finned fish had both gills & lungs
AMPHIBIANS-
VERTEBRATES INVADE THE LAND
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Desiccation:
– Had to return to water
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Reproduction:
– Soft-covered eggs had to be laid in water
AMPHIBIANS-
VERTEBRATES INVADE THE LAND
AMPHIBIANS-
VERTEBRATES INVADE THE LAND
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Labyrinthodonts:
– Early group of amphibians
– Similar traits as crossopterygian lobe-finned fish
– Late Devonian
AMPHIBIANS-
VERTEBRATES INVADE THE LAND
REPTILES
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Desiccation: reptiles
overcame w/ skin that didn’t dry out
REPTILES
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Reproduction: reptiles
overcame w/ amniote egg
–
Hard-shelled egg w/
embryo in liquid-filled sac
–
Produces miniature adult
(no larval stage)
–
Major evolutionary step
–
Late Mississippian
REPTILES
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Includes pelycosaurs:
REPTILES
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Permian: pelycosaurs go
extinct
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Replaced by therapsids:
– Mammal-like reptiles
– Evolved fr. carnivorous pelycosaurs
REPTILES
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Early therapsid
mammal-like features:
– Warm-blooded?
– Skeletal structure
REPTILES
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Permian/Triassic mass
extinction:
– Great affect on marine invertebrates (90%)
– 2/3 of amphibians & reptiles
– Lesser affect on plants
PLANT
EVOLUTION
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Ancestors of land
plants:
– 1st evolved in marine environment
– Move to freshwater
– Then moved to land
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Earliest land plants:
– M. to L. Ordovician
– Nonvascular plants: no vessels for moving
water/nutrients
PLANT
EVOLUTION
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Seedless vascular
plants:
PLANT
EVOLUTION
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Seedless vascular
plants:
PLANT
EVOLUTION
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Gymnosperms
(“naked seed”)
– Plants w/ seeds but no flowers
– Does not require moist environment
– Includes seed ferns & conifer-type seed plants
– By L. Devonian
PLANT
EVOLUTION
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Includes glossopteris flora
PLANT
EVOLUTION
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Summary of Pz plant
evolution:
–
Marine, freshwater, land
–
M. to L. Ordovician: nonvascular
plants
–
M. Silurian: seedless
vascular plants (Pennsylvanian coal swamps)
–
L. Devonian: gymonsperms
(seeds but no flowers; incl. glossopteris)
INSECT
EVOLUTION
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Devonian: wingless
insects
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Mississippian: insects
w/ non-foldable wings
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Carboniferous:
increasing size