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Eras of Earth’s History EQ: What causes changes in the Earth? How does knowing the past give us a VISION for the future?

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Presentation on theme: "Eras of Earth’s History EQ: What causes changes in the Earth? How does knowing the past give us a VISION for the future?"— Presentation transcript:

1 Eras of Earth’s History EQ: What causes changes in the Earth? How does knowing the past give us a VISION for the future?

2 Precambrian Time Eon

3  4.6 billion years ago-545 million years ago  Information about this time on Earth is SCARCE  Rocks are buried deep within Earth’s Crust  Information on rocks damaged or destroyed by Earth’s inner heat and pressure of other rock layers  Moon forms during this time

4 Precambrian Eon continued….  Earth originally thought to be “dead”  Volcanoes produce toxic atmosphere  Water and water Vapor that form the oceans comes from volcanoes, asteroids and comets!!!

5 *Precambrian Eon continued….*  Closer look at rocks show Signs of cynobacteria  Cynobacteria-changed Earth’s past atmosphere of water vapor, ammonia and methane into Nitrogen and Oxygen: STILL FOUND ALIVE TODAY in deep sea Thermal Vents and in volcanoes  Today’s atmosphere made up of nitrogen, oxygen and water vapor

6 Phanerozoic Eon (3 Eras) * Paleozoic Era: m.y.a.: Basic Traits*  The longest of all the Eras on the Earth  Contains 7 periods  Fossils of large organisms first found in this era  Almost all are marine environment  Largest land Continent called Gondwana (begins with 90 % of Earth’s surface covered by water)  Warm Earth; Life limited to oceans; ozone layer not fully developed: no plants on land intially  Ends with the largest mass extinction in Earth’s history (90% of all life killed)

7 *Why did life first start in the ocean?*  More stable environment: Water 22x heat capacity than air  UV Protection: –DNA Damaged by UV radiation –DNA contains all information for life –Earth’s ozone layer just starting to develop from oxygen produced by cynobacteria

8 *Why did life first start in the ocean?*  Gravity’s affect neutralized  -organisms would develop in environment in which gravity would have no impact on animal’s structure –NO need for powerful muscles to move

9 *Why did life first start in the ocean?*  Easier to obtain minerals and gases necessary for life  Water naturally has these items dissolved in it  Organisms could just absorb materials as water passed by

10 *Easier to obtain food*  Food would be suspended in 3 dimensions: filter feeding or feeding with tentacles become popular

11 7 periods of Paleozoic Era  Cambrian Period ( ) –Trilobites –Clams –Inland seas suggest warm Earth –Land Formation: supercontinent Gondwana; (S hemisphere)

12 Ordovician Period ( )  First land plants (ferns)  First vertebrates: early fish appear  Life moves into shallower water: Suggests ozone layer almost fully developed as life moves closer to land  Laurussia seperates from Gondwana

13 Silurian Period ( )  Corals Dominate World’s Oceans  Warm Earth  Plants move further inland  Animals now moving further inland by way of water; fresh water fish  N. America covered by shallow sea

14 *Devonian Period ( )*  Fish dominate oceans  First amphibians  Signs of Earth beginning to cool: Water retreats forcing organisms to adapt to the new changes. More land created

15 Mississippian Period ( )  Amphibians dominate land life  Earth much cooler as glaciers move southward from polar regions  Cooler Earth forces Amphibians to adapt to changes; (less water-thicker skin)

16 Pennsylvanian Period ( )  First reptiles and insects  Shallow seas over N.America almost disappeared  Cooler Earth

17 *Permian Period ( )*  Glaciers retreat  Earth Warming back up  Ends with largest mass extinction in fossil record (Asteroid impact)

18 *Mesozoic Era *  AGE OF DINOSAURS  Million Years Ago  Split into 3 major periods  Triassic period ( million years)  Jurassic Period ( million years)  Cretaceous Period ( million years)

19 Triassic Period  Marks beginning of Mesozoic Era  First dinosaurs and mammals appeared around 225 million years ago  Atlantic Ocean  Pangaea breaks up  Flowering Plants appear  Eoraptor, Plateosaurus and Teratosaurus

20 *Why Dinosaurs Evolve*  Environmental Factors- As Pangaea break apart each land mass gets a unique climate  Disease Influence- Diseases possible reason species die out  Competition for Food- organisms compete for same food sources; winners live losers die  Predatory Influence- animals develop defenses against Predators

21 Jurassic Period ( )  Flowering Plants and Dinosaurs dominate land  Birds appear  Appalachian Mountains Form  Dinosaurs become more diverse from basic shapes  Allosaurus  Stegosaurus  Diplodicus  Ceratosaurus

22 Cretaceous Period (144-65)  Most advanced dinosaurs: Highly specialized, most successful of all dinosaur species  Modern Earth Appears  Ends in Mass Extinction of Dinosaurs  Tyrannosaurs, Tricerotops, Ankylosaurus, Protocerotype, Velocoraptors, Pterodactyl

23 Comparison of the Dinosaurs TriassicJurassicCretaceous small (Stegosaurus) Med- large T-rex, Triceraptops, Raptors Largest Cold bloodedWarm blooded Reptile-likeMore AdvancedMost Advanced/ Bird like in many ways Simple body plans 4 legs herbivores 2 legs carnivores Defenses against Preadtors Most advanced features Hollow bones (t rex, raptors) Proto-feathers on skin Each continent had its own unique Dinosaurs

24 *Meteorite Theory?*  Says that asteroid/comet 3-5 miles wide struck near Yucatan Peninsula and caused Dinosaur Extinction  Iridium deposits in KT layer help support this  However, closest Dinosaur bones ever found date about 1,000 prior to event  Climate Change/Disease reason for extinction??

25 *Cenozoic Era*  Continents were drifting apart—present time of Earth  African plate collided with European plate creating the Alps  India slammed into Asian plate creating Himalayas  Climate was cooled causing several “ice ages”

26 *Mammals Survive because*  Small size easier to maintain body temperature in climate change  Ability to Hibernate during an extreme event  Mothers provide food for young from milk, No other organisms do this (mammals unique)

27 Cenozoic Era  Age of Mammals (65mya- present day)  2 Periods

28 Tertiary Period (65mya – 1.6mya)  Earth’s climate was warm and mild  Ocean mammals like dolphins and whales evolve  Land-insects, flowering plants and mammals, birds dominate  Mega mammals mammals evolve  Alps and Himalayas Form

29 Quaternary Period: (1.6 mya- today)  Mega mammals die out/ (Climate Change?)  Present period  Humans appear—100,000 years ago  Grand Canyon forms  Last ice age 15,000-10,000 years ago


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