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Biogeography. Lecture 5
Alexey Shipunov
Minot State University
January 29, 2014
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 1 / 34
Outline
PalaeogeographyPlate tectonics
Most important eras and periodsCryogenian period (850–635 Mya) and Snowball EarthEdiacarian period: 635–550 MyaCambrian periodOrdovician, Silurian and Devonian: three ages of fishes
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 2 / 34
Outline
PalaeogeographyPlate tectonics
Most important eras and periodsCryogenian period (850–635 Mya) and Snowball EarthEdiacarian period: 635–550 MyaCambrian periodOrdovician, Silurian and Devonian: three ages of fishes
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 2 / 34
Palaeogeography Plate tectonics
PalaeogeographyPlate tectonics
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 3 / 34
Palaeogeography Plate tectonics
Mantle convection
I The driving force of floating continents is a mantle convectionI In ocean ridges, new ocean cortex is constantly forming and
expandingI In ocean trenches and continental ridges, different plates are
colliding and often forming mountains
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Palaeogeography Plate tectonics
Mantle convection
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 5 / 34
Palaeogeography Plate tectonics
Mantle convection
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 6 / 34
Palaeogeography Plate tectonics
The result of mantle convection
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Palaeogeography Plate tectonics
What is going on now
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Palaeogeography Plate tectonics
Two living examples of continental drift on U.S. territory
I Yellowstone hotspotI Hawaiian hotspot
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Palaeogeography Plate tectonics
Yellowstone hotspot
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 10 / 34
Palaeogeography Plate tectonics
Hawaiian hotspot
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 11 / 34
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth
Most important eras andperiods
Cryogenian period (850–635 Mya)and Snowball Earth
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 12 / 34
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth
Rodinia—the first super-continent
I Tectonic plates formed (and will form) one continent several timesI 650 Mya this continent—Rodinia was formed right over the South
Pole
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 13 / 34
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth
Cryogenian continents which formed Rodinia
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 14 / 34
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth
Rodinia: view from South Pole
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 15 / 34
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth
Marionan glaciation: Snowball Earth
I First global glaciation was started because ice started toconcentrate over the pole and increase Earth albedo (this is thepositive feedback)
I And because the configuration of continents blocked theequatorial warm current
I And because concentration of oxygen was high but greenhousegases (like CO2)—small
I As a result, from time to time Earth was completely covered withice sheet 1 km tall!
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Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth
Star Wars Hoth—ice planet
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 17 / 34
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth
Snowball Earth
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 18 / 34
Most important eras and periods Ediacarian period: 635–550 Mya
Most important eras andperiods
Ediacarian period: 635–550 Mya
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 19 / 34
Most important eras and periods Ediacarian period: 635–550 Mya
Rodinia breaks
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Most important eras and periods Ediacarian period: 635–550 Mya
Ediacarian continents
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 21 / 34
Most important eras and periods Ediacarian period: 635–550 Mya
Life in Cryogenian and Ediacarian
I Before: prokaryotes, included photosynthetic (cyanobacteria),then unicellular eukaryotes
I Cryogenian: multicellular eukaryotes, e.g. algaeI Ediacarian: first animals
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Most important eras and periods Ediacarian period: 635–550 Mya
Ediacarian life
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 23 / 34
Most important eras and periods Cambrian period
Most important eras andperiods
Cambrian period
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 24 / 34
Most important eras and periods Cambrian period
Cambrian map
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 25 / 34
Most important eras and periods Cambrian period
Cambrian climate and life
I Gradually changed from colder to warmerI Cambrian explosion: appearance of most of animal phyla with
skeletonI Little or no terrestrial lifeI The main driver of animal evolution during Cryogenian–Cambrian
was probably oxygenation of waterI One theory states that pre-Cambrian ocean water was muddy and
rich of organic compounds, animal filtration changed this condition
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Most important eras and periods Cambrian period
Cambrian life
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 27 / 34
Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes
Most important eras andperiods
Ordovician, Silurian and Devonian:three ages of fishes
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 28 / 34
Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes
Ordovician period
I Climate changed from hot to glaciated (Gondwana hits the South Pole)
I Marine fauna spread out, especially cephalopods, conodonts andgraptolites
I In the end, the first great extinction: 85% of marine species extinct
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 29 / 34
Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes
Silurian period
I Fluctuating climate
I Prospering of marine fauna again
I Land colonization started from plants and arthropods!
I South Pole still in the Gondwana
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Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes
Silurian sea
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Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes
Devonian period
I Moderate climate becoming warmer
I Exceptionally high sea level
I Greatest diversity of marine fauna in Paleozoic (especially fishes)
I Terrestrial vertebrates: tetrapods appeared!
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 32 / 34
Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes
Summary
I Continents of Earth are constantly changing their position due tothe mantle convection (“plate tectonics”)
I From Cryogenian to Ordovician, super-continent Rodinia brokeand climate on Earth became milder
I Most of water-inhabiting animal groups appeared by Ordovician
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 33 / 34
Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes
For Further Reading
A. Shipunov.Biogeography [Electronic resource].2014—onwards.Mode of access:http://ashipunov.info/shipunov/school/biol_330
Plate tectonics.http://en.wikipedia.org/wiki/Plate_tectonics
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