12/02/2013
Week 3 – Cambrian Explosion
What was the Cambrian Explosion?
1 12/02/2013
Cambrian Explosion
Period of geological time when nearly every metazoan phylum appears
Metazoa
2 12/02/2013
Metazoan phyla
Cambrian: how explosive? When did it start? What appeared when?
3 12/02/2013
Beginning of the Cambrian
Terreneuvian: Fortunian
542 Ma
Ediacaran-Cambrian boundary = 542 Ma
Global Stratotype Section and Point (GSSP), Fortune Head, Newfoundland, Canada
4 12/02/2013
Ediacaran-Cambrian boundary
Ediacaran microbial mats
Callow & Brasier (2009)
5 12/02/2013
The Cambrian burrow
Treptichnus pedum (made by priapulid worms?)
Fortunian burrows
Gyrolithes
6 12/02/2013
Small shelly fossils
Scale bars = 0.1 mm
Halkieriids
Lots of sclerites
7 12/02/2013
Early Cambrian: Stage 2
The first metazoan reefs
Archaeocyathid limestones, Labrador
8 12/02/2013
The first brachiopods
Lingulids still around today
Early Cambrian: Stage 3
9 12/02/2013
Trilobites!
Chengjiang
10 12/02/2013
Our long- lost sister?
Haikouella lanceolata
Found in 1999
Head, gills, notochord...
=chordate
Middle Cambrian
Burgess Shale
11 12/02/2013
Arthropods!
Opabinia
Burgess Shale
12 12/02/2013
Burgess Scale
How did the Cambrian explode?
13 12/02/2013
Increasing oxygen
Oxygen at ~10% Present Atmospheric Levels (PAL) to support animal life?
Cambrian Substrate Revolution
Nutrient cycling New ecospace
14 12/02/2013
Ediacaran extinction?
Where did metazoan phyla come from?
A bit like mammals?
Long fuse; Sudden post- extinction burst
15 12/02/2013
Next week
The Great Ordovician Biodiversification Event
Useful websites
Royal Ontario Museum: Burgess Shale: http://burgess-shale.rom.on.ca/en/index.php Long fuse of the Cambrian Explosion: http://www.geol.umd.edu/~tholtz/G204/lectures/204cambrian.html An online guide to trilobites: http://www.trilobites.info/ Halkieriids: http://en.wikipedia.org/wiki/Halkieriid
16 12/02/2013
Useful websites (2)
Chengjiang UNESCO World Heritage: http://whc.unesco.org/en/list/1388
17