Eras of Earth’s History - PowerPoint Presentation

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

Precambrian Time Eon

Precambrian Time Eon 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

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!!!

*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

Phanerozoic Eon (3 Eras) * Paleozoic Era: 545-245m.y.a.: Basic Traits* The longest of all the Eras on the EarthContains 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)

*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 lifeEarth’s ozone layer just starting to develop from oxygen produced by cynobacteria

*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 structureNO need for powerful muscles to move

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

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

7 periods of Paleozoic Era Cambrian Period (545-505) TrilobitesClamsInland seas suggest warm Earth Land Formation: supercontinent Gondwana; (S hemisphere)

Ordovician Period (505-438) First land plants (ferns) First vertebrates: early fish appearLife moves into shallower water: Suggests ozone layer almost fully developed as life moves closer to land Laurussia seperates from Gondwana

Silurian Period (438-408) Corals Dominate World’s Oceans Warm EarthPlants move further inlandAnimals now moving further inland by way of water; fresh water fish N. America covered by shallow sea

*Devonian Period (408-360)* Fish dominate oceans First amphibians Signs of Earth beginning to cool: Water retreats forcing organisms to adapt to the new changes. More land created

Mississippian Period (360-320) 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)

Pennsylvanian Period (320-286) First reptiles and insects Shallow seas over N.America almost disappeared Cooler Earth

*Permian Period (286-245)* Glaciers retreat Earth Warming back upEnds with largest mass extinction in fossil record (Asteroid impact)

*Mesozoic Era * AGE OF DINOSAURS 245-65 Million Years AgoSplit into 3 major periodsTriassic period (245-208 million years) Jurassic Period (208-144 million years)Cretaceous Period (144-65 million years)

Triassic Period Marks beginning of Mesozoic Era First dinosaurs and mammals appeared around 225 million years agoAtlantic Ocean Pangaea breaks upFlowering Plants appearEoraptor, Plateosaurus and Teratosaurus

*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 diePredatory Influence- animals develop defenses against Predators

Jurassic Period (208-144) Flowering Plants and Dinosaurs dominate land Birds appearAppalachian Mountains FormDinosaurs become more diverse from basic shapes AllosaurusStegosaurusDiplodicusCeratosaurus

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

Comparison of the Dinosaurs Triassic Jurassic Cretaceous small (Stegosaurus) Med- large T- rex , Triceraptops , Raptors Largest Cold bloodedWarm bloodedWarm bloodedReptile-likeMore Advanced Most 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

*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 eventClimate Change/Disease reason for extinction??

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

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

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

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 evolveAlps and Himalayas Form

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