Biogeography. Lecture 5
Alexey Shipunov
Minot State University
January 29, 2014
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 1 / 34 Outline
Palaeogeography Plate tectonics
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth Ediacarian period: 635–550 Mya Cambrian period Ordovician, Silurian and Devonian: three ages of fishes
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 2 / 34 Outline
Palaeogeography Plate tectonics
Most important eras and periods Cryogenian period (850–635 Mya) and Snowball Earth Ediacarian period: 635–550 Mya Cambrian period Ordovician, Silurian and Devonian: three ages of fishes
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 2 / 34 Palaeogeography Plate tectonics
Palaeogeography Plate 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 convection
I In ocean ridges, new ocean cortex is constantly forming and expanding
I In ocean trenches and continental ridges, different plates are colliding and often forming mountains
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 4 / 34 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
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 7 / 34 Palaeogeography Plate tectonics What is going on now
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 8 / 34 Palaeogeography Plate tectonics Two living examples of continental drift on U.S. territory
I Yellowstone hotspot
I Hawaiian hotspot
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 9 / 34 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 and periods 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 times
I 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 to concentrate over the pole and increase Earth albedo (this is the positive feedback)
I And because the configuration of continents blocked the equatorial warm current
I And because concentration of oxygen was high but greenhouse gases (like CO2)—small I As a result, from time to time Earth was completely covered with ice sheet 1 km tall!
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 16 / 34 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 and periods 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
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 20 / 34 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. algae
I Ediacarian: first animals
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 22 / 34 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 and periods 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 warmer
I Cambrian explosion: appearance of most of animal phyla with skeleton
I Little or no terrestrial life
I The main driver of animal evolution during Cryogenian–Cambrian was probably oxygenation of water
I One theory states that pre-Cambrian ocean water was muddy and rich of organic compounds, animal filtration changed this condition
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 26 / 34 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 and periods 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 and graptolites
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
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 30 / 34 Most important eras and periods Ordovician, Silurian and Devonian: three ages of fishes Silurian sea
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 31 / 34 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 to the mantle convection (“plate tectonics”)
I From Cryogenian to Ordovician, super-continent Rodinia broke and 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
Shipunov (MSU) Biogeography. Lecture 5 January 29, 2014 34 / 34