THE DAWN OF ANIMALS:
LESSONS FROM AROUND THE WORLD
Marc Laflamme, marc.laflamme@utoronto.ca
Archean Microfossils:
Stromatolites
Schopf, Elements (2006)
Proterozoic Life
Bangiomorpha Proterocladus Dolores Creek Macrofossils Apatitic scale microfossils
Grypania Chuaria
Cohen et al. 2017
1 cm 20μm 200 μm 2 mm
Han and Runnegar 1992 Tang et al. 2017 Butterfield 2000 Tang et al. 2020 Maloney et al. 2021
OL YOUNG
D
1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8
First Great First
First
First life oxygen-producing Oxidation “Boring Billion” Animals
Eukaryotes
bacteria Event appear
4.5 4.0 3.5 3.0 2.5 2.0 1.8 1.5 1.0 0.8 0.5 Modern Day
Billion Years
Evidence for glaciations
Dropstones: Isolated rocks found in
smoothly laminated marine
sediments that are interpreted as
having fallen from melting icebergs
Ediacara Biota
Precambrian (579-541 Ma)
Entirely soft bodied
Primitive animals and
extinct organisms
Complex shapes and
ecosystems
Entirely soft bodied
Primitive animals and extinct organisms
Animals Vendobionta
Photos by G. Gehling Seilacher, 1992
Primitive animals: Molluscs
Kimberella
Fedonkin et al, 2007
Primitive animals: Molluscs
Photo by J. Vinther
… and extinct organisms: Rangeomorphs
• Modular, repetitive branching
• Feeding unit: lacking a mouth,
gut, tentacles, or pores
• Deep and shallow-water settings
• Namibia, Australia, England,
Newfoundland, northern Canada
Where do we go? Newfoundland!
Present Day
Laflamme et al., 2013
Photo by S. Tweedt
Photo by Greg Locke
Mistaken Point
2016 UNESCO World Heritage Site
Photo by S. Tweedt
Photo by S. Tweedt
Mistaken Point
Photo by Greg Locke
Photo by G. Narbonne
Environmental context
Deep water environment
Marine, not terrestrial, environment
No light for photosynthesis
Conclusions: Organisms at Mistaken Point could not
use light as a food source.
Is this the case everywhere around the world?
Environmental Controls on Distribution
Were the Ediacara biota controlled by
environmental factors?
What we need:
1. An understanding of the environmental context
2. Numerous different environments as interpreted from
the local geology
3. Large surfaces with complete communities and a
diverse assay of species
Case Study 2: Australia
Australia Environmental Context
Shallow- and deep-
water ecosystems with a
diverse array of
different ecosystems
called Facies:
A group of rocks and
primary sedimentary
structures indicative of
a given depositional
environment.
Australian Ediacaran Facies
Xiao and Laflamme, 2009
Ediacaran Extinction, Cambrian Explosion
What is the relationship between the
disappearance of the Ediacara biota, and the
emergence of complex animals?
What we need:
1. Sections where animals and Ediacarans overlap
2. An understanding of the environmental context
3. Precise radiometric dates
Case Study 3: Namibia
Farm Swartpunt,
Namibia
Treptichnids - the evolution of complex behaviors
Turk et al., 2022
Photo by D. Erwin
(Erwin et al. 1997)
