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EARLY PALEOZOIC LIFE
Cambrian Explosion
Evolution’s “big bang”
lasted about 10 million years
All principal animal phyla except Bryozoaappeared between 535 to 520 myBP
The Cambrian Explosion
EARLY PALEOZOIC LIFE
By the Ordovician, global biodiversity tripled
Included trilobites, brachiopods, bivalve molluscs,gastropods and coralline animals
Ordovician mountain building may have created new habitats
The number of infaunal organisms increased
Continuing Diversification
EARLY PALEOZOIC LIFE
Foraminifera
First appeared in the CambrianSurvive to present
Unicellular Organisms (Protistans)
Platysolenites, a Cambrian foramAgglutinated form
Calcareous skeleton
EARLY PALEOZOIC LIFE
Radiolaria
First appeared in the Cambrian, more abundant inmid-Paleozoic
Survive to presentHave a siliceous skeleton
Unicellular Organisms (Protistans)
EARLY PALEOZOIC LIFE
Archeocyathids (“ancient cup”)
Early Cambrian phylum
Have similarities to both corals and sponges
Associated with stromatolites
Reef-builders of Early to Middle Cambrian60 m thick, 200 km long
Extinct at end of Cambrian
Metazoan Invertebrates
EARLY PALEOZOIC LIFE
Archeocyathids (“ancient cup”)
Metazoan Invertebrates
EARLY PALEOZOIC LIFE
Phylum Porifera (sponges)
Early Cambrian phylum
Evolved from colonial flagellated, unicellular organisms
Conservative evolutionary history
All but one modern class of sponges were present inCambrian
Exist to present
Metazoan Invertebrates
EARLY PALEOZOIC LIFE
Phylum Porifera (sponges)
Metazoan Invertebrates
EARLY PALEOZOIC LIFE
Phylum Porifera (sponges) SPICULES
Metazoan Invertebrates
Spicules –
Composed of
Calcium carbonate
EARLY PALEOZOIC LIFE
Phylum Porifera (sponges) SPICULES
Metazoan Invertebrates
Spicules –
Composed of
Silica
EARLY PALEOZOIC LIFE
Phylum Porifera (sponges) SPICULES
Metazoan Invertebrates
Spicules –
Composed of
Spongin
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Phylum Porifera (sponges)Cambrian
Protospongia
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Phylum Porifera (sponges)Ordovician
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Phylum Porifera (sponges)Silurian
Astylospongia
Caryospongia
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Phylum Porifera (sponges)Silurian
Palaeomanon
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Phylum Porifera (sponges)Silurian
AstraeospongiaStar-shaped spicules
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Stromatoporoids
Calcareous sponges
Geologic range: Ordovician to Present
Built reefs in the Silurian (Michigan Basin)
Found in Caribbean Sea, Mediterranean Seaand Pacific Ocean
EARLY PALEOZOIC LIFEMetazoan Invertebrates
StromatoporoidsSide view
Laminae and Pillar Structure
EARLY PALEOZOIC LIFEMetazoan Invertebrates
StromatoporoidsTop view
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Cnidaria (Coelenterata or Corals)
Includes
Sea fansJellyfishAnemonesCorals
Very diverse groupStinging cells – cnidocytesRadially symmetrical
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Cnidaria (Coelenterata or Corals)
Jellyfish
Fire coral
Sea fans, gorgonian
Horn corals
Tabulate corals
Modern corals
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Cnidaria (Coelenterata or Corals)
Two forms:
Polyps and Medusa
Polyps – asexual
Medusa - sexual
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Cnidaria (Coelenterata or Corals)
Stinging cellsCnidocytes
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Cnidaria (Coelenterata or Corals)
Stinging cells or Cnidocytes
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Rugosa (Rugose or Horn Corals)
Ranged from Ordovician to Permian
Not major reef formers, colonizers
Usually solitary
Abundant in Silurian and Devonian reefs
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Rugosa (Rugose or Horn Corals)
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Rugosa (Rugose or Horn Corals)
EARLY PALEOZOIC LIFEMetazoan Invertebrates
Rugose growth