Earth s Tectonic History

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1 Earth s Tectonic History CANADA EUROPE SIBERIA CHINA AUSTRALIA 0.05 mya (Pleistocene - glacia4ons) h;p://jan.ucc.nau.edu/~rcb7/globaltext2.html Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous TerQary Paleozoic Mesozoic Cenozoic Phanerozoic mya

2 1) ShiFing PaGern of Isola4on and Connectedness The separaqon of conqnents provided opportuniqes for allopatry on a grand scale Recall the importance of isola1on in diversifica1on via allopatric specia1on Similarity (%) This study compares the similarity in (mammal) species composiqon between pairs of landmasses (each point is a paired comparison) Versus the distance that separates those landmasses in each pair Landmasses include: NA, SA, Africa, Eurasia, New Guinea, Madagascar and Australia (A) (the distance along the route that minimizes overwater travel) (figure from Flessa 1980) 2

3 1) ShiFing PaGern of Isola4on and Connectedness Similarity (%) 1) Mammal bioqc similarity decreases as overland distance between landmasses increases 2) Most pairwise comparisons with Australia (A) fall below trend line (more disqnct due to long isolaqon of Australian conqnent) (the distance along the route that minimizes overwater travel) (figure from Flessa 1980) 3

4 1) ShiFing PaGern of Isola4on and Connectedness 185 mya Similarity in marine invertebrate (fossil) composiqon decreases as distance between western and eastern AtlanQc basins increases over Qme Similarity (%) As mid-atlanqc ridge pushed conqnental plates apart, AtlanQc Ocean formed and got bigger Increasing isolaqon of marine invertebrate faunas on either side of ridge with opportunity for divergence 18 mya J = Jurassic; K = Cretaceous P = Paleogene; N = Neogene (figure from Flessa 1980) 4

5 1) ShiFing PaGern of Isola4on and Connectedness Bio4c Exchanges (from Vermeij 1991) 5

6 1) ShiFing PaGern of Isola4on and Connectedness Pleistocene TerQary Cretaceous Jurassic Great American Bio4c Exchange Timeline of Events: mya: N and S America part of Gondwanaland. Origin, diversificaqon and spread of mammals and birds. 140 mya: IsolaQon of S America. 65 mya: N and S America approaching present configuraqon. Major exqncqons (including dinosaurs). Meteor impact at Chicxulub (Gulf of Mexico). 3.5 mya: Emergence of Central American land bridge mya: Lowering sea levels and extension of savanna biome in Central America during glacial maxima. Major bioqc exchanges between N. and S. America. 6

7 1) ShiFing PaGern of Isola4on and Connectedness Mammals of N and S America before exchange: Shrews Pocket mice Pocket gophers Beavers Pronghorns Bison Rabbits Field mice Foxes Bears Raccoons Weasels Cats Mastodons Horses Tapirs Peccaries Camels Deer Porcupines Glyptodonts Armadillos Giant ground sloths Opossums Primates Octodonts Spiny rats Nutrias AgouQs Capybaras Cavies Three-toes sloths Two-toed sloths Anteaters Shrew opossums 7

8 1) ShiFing PaGern of Isola4on and Connectedness Exchange of Mammals of N and S America: Shrews Pocket mice Pocket gophers Beavers Pronghorns Bison Rabbits Field mice Foxes Bears Raccoons Weasels Cats Mastodons Horses Tapirs Peccaries Camels Deer Porcupines Glyptodonts Armadillos Giant ground sloths Opossums Primates Octodonts Spiny rats Nutrias AgouQs Capybaras Cavies Three-toes sloths Two-toed sloths Anteaters Shrew opossums 8

9 1) ShiFing PaGern of Isola4on and Connectedness Reasons for asymmetric bio4c exchange: 1. N American mammals were be;er migrators could be due to the fact that there were more savanna specialists in N America, and conqnuous savanna through the land bridge. 2. They were be;er survivors S American mammals tended to be closed-forest specialists, and forest habitat became fragmented with climate change (smaller populaqons, more exqncqon). 3. They were be;er compeqtors (?) maybe No clear reason for differenqal success. 9

10 1) ShiFing PaGern of Isola4on and Connectedness Exchange of Birds of N and S America: Pigeons Owls Woodpeckers Jays Hummingbirds Tyrant flycatchers Vireos Wood warblers Blackbirds Orioles Tanagers Emberizine bunqngs 10

11 1) ShiFing PaGern of Isola4on and Connectedness Other Vertebrates of N and S America: Some show opposing pa;erns, but almost always with unbalanced exchange. 11

12 2) Changing Amounts of Land and Sea Area The proporqon of landmass at different laqtudes has nearly reversed since 425 mya from south of the equator (lined area) to north (beige plain area) When landmasses drined over the poles, they triggered cycles of glaciaqon and changes in sea level 12

2) Changing Amounts of Land and Sea Area Diversity of ammonites Class Cephalopoda Spiral shaped fossilized shells Index fossils can be used to link the rock layer in which they

13 2) Changing Amounts of Land and Sea Area Diversity of ammonites Class Cephalopoda Spiral shaped fossilized shells Index fossils can be used to link the rock layer in which they are found to specific geological Qme periods ExQncQon events in the marine realm can be linked to changes in sea level, which altered the area of conqnents covered by shallow seas 13

14 3) Climate Change Zoogeographic Consequences The breakup of Panaea promoted circum-equatorial Tethyan seaway current Following breakup of Australia and AntarcQca, the southern margins of Australia were exposed to cool currents Cool dry air masses along southern margins of Australia were likely a major driving force generaqng the great central deserts 14

15 3) Climate Change Zoogeographic Consequences Drop in number of families (exqncqon) around Qme of Pangaea formaqon (between Permain P and Triassic TR Periods Rapid increase in number of families (diversificaqon) aner beginning of Pangaea breakup in the Jurassic Period J 15

4) Hydrothermal Vents and Tectonically-Derived Faunas High temperature environments with high hydrogen sulfide concentraqon around ridges of sea floor spreading Discovery in 1977 of whole deep water

16 4) Hydrothermal Vents and Tectonically-Derived Faunas High temperature environments with high hydrogen sulfide concentraqon around ridges of sea floor spreading Discovery in 1977 of whole deep water communiqes (>6000m deep) based on chemosynthesis Highly disqnct because: 1. very isolated 2. very old (originated over 400 mya) 3. highly specialized adaptaqons Discovery resulted in recogniqon of a new phylum: VesQmenQfera, with 14 families, and >50 genera (includes highly unusual tube worms) 16

17 4) Hydrothermal Vents and Tectonically-Derived Faunas Color circles show vents with similar animal communiqes (from h;p:// 17

18 References for this sec4on: ConQnental Drin Flessa, K.W Biological effects of plate tectonics and conqnental drin. Bioscience 30: Lomolino, M.V., B.R. Riddle, R.J. Whi;aker, & J.A. Brown Biogeography (4 th ed., Chapter 2). Sinauer Associates, Inc., Sunderland, Mass. USGS website on plate tectonics: h;p://pubs.usgs.gov/gip/dynamic/dynamic.html 18

19 InteresQng quesqons with plate tectonics 1) Do other planets have plate tectonics? For years, many scienqsts had thought that plate tectonics existed nowhere in our solar system but on Earth. In 2012, a UCLA scienqst has discovered that the geological phenomenon, which involves the movement of huge crustal plates beneath a planet's surface, also exists on Mars Mars is at a primiqve stage of plate tectonics. It gives us a glimpse of how the early Earth may have looked and may help us understand how plate tectonics began on Earth

20 InteresQng quesqons with plate tectonics 2) What will our conqnents look like 250 million years from now? h;ps://

The Phanerozoic Eon. 542 mya Present. Divided into 3 Eras The Paleozoic, Mesozoic, and Cenozoic Eras

The Phanerozoic Eon. 542 mya Present. Divided into 3 Eras The Paleozoic, Mesozoic, and Cenozoic Eras 542 mya Present The Phanerozoic Eon Divided into 3 Eras The Paleozoic, Mesozoic, and Cenozoic Eras The ends of the Paleozoic and Mesozoic Eras were marked by mass extinctions The Cenozoic Era is still