ediacarans, small shells and the dawn of the phanerozoic
TRANSCRIPT
![Page 1: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/1.jpg)
Ediacarans, Ediacarans, Small Shells Small Shells
and the Dawn and the Dawn of the of the
PhanerozoicPhanerozoic
![Page 2: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/2.jpg)
Edicaran BiotaEdicaran Biota
• First fossils of multicellular organisms• Some controversy
– Multicellular life?– Colonies of single cells?
• Definitely not single cells• Signs of tissue differentiation• Advanced symmetry
![Page 3: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/3.jpg)
Ediacaran (Vendozoan)BiotaEdiacaran (Vendozoan)Biota
![Page 4: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/4.jpg)
Taphonomy of theTaphonomy of theEdicaran BiotaEdicaran Biota
• Soft/firm bodied?• Molds and casts in coarse sandstone• Facies preference?• Taphonomic bias?
![Page 5: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/5.jpg)
Radial and Bilateral Radial and Bilateral SymmetrySymmetry
![Page 6: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/6.jpg)
Radial SymmetryRadial Symmetry
![Page 7: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/7.jpg)
Bilateral Symmetry and Bilateral Symmetry and Differentiated StructuresDifferentiated Structures
![Page 8: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/8.jpg)
Symmetry and DiversitySymmetry and Diversity
![Page 9: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/9.jpg)
Filter Feeders?Filter Feeders?
![Page 10: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/10.jpg)
Differentiated Structures, Differentiated Structures, But Which End Was Up?But Which End Was Up?
![Page 11: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/11.jpg)
Significant Diversity or Significant Diversity or Variations on a Single Theme?Variations on a Single Theme?
![Page 12: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/12.jpg)
Dawn of the Phanerozoic: Small Dawn of the Phanerozoic: Small Shelly Fauna and TrilobitesShelly Fauna and Trilobites
![Page 13: Ediacarans, Small Shells and the Dawn of the Phanerozoic](https://reader030.vdocuments.us/reader030/viewer/2022032516/56649c6e5503460f94920d37/html5/thumbnails/13.jpg)
What Do We Choose as the What Do We Choose as the Start of the Cambrian?Start of the Cambrian?
• Extinction of the Ediacarans?• First appearance of the ”small shelly fauna”?
– Late Proterozoic
• First trilobites? – Part of “Cambrian Explosion”– Lower, but not lowest Cambrian
• First trace fossils of trilobites?• First evidence of mobility (burrows)?• First burrows chosen