Date post: | 11-Dec-2015 |
Category: |
Documents |
Upload: | jaden-askey |
View: | 222 times |
Download: | 6 times |
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 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)
*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
*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
*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
*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) – Trilobites– Clams– Inland seas suggest
warm Earth– Land Formation:
supercontinent Gondwana; (S hemisphere)
Ordovician Period (505-438)¨ 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
Silurian Period (438-408)¨ 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
*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 up¨ Ends with largest mass extinction in fossil
record (Asteroid impact)
*Mesozoic Era *
¨ AGE OF DINOSAURS¨ 245-65 Million Years Ago¨ Split into 3 major periods¨ Triassic 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 ago¨ Atlantic Ocean¨ Pangaea breaks up¨ Flowering Plants appear¨ Eoraptor, 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 die
¨ Predatory Influence- animals develop defenses against Predators
Jurassic Period (208-144)
¨ Flowering Plants and Dinosaurs dominate land¨ Birds appear¨ Appalachian Mountains Form¨ Dinosaurs become more diverse from basic shapes¨ Allosaurus¨ Stegosaurus¨ Diplodicus¨ Ceratosaurus
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
Comparison of the DinosaursTriassic Jurassic Cretaceous
small(Stegosaurus)Med- large
T-rex, Triceraptops, RaptorsLargest
Cold blooded Warm blooded Warm blooded
Reptile-like More Advanced Most Advanced/ Bird like in many ways
Simple body plans4 legs herbivores2 legs carnivores
Defenses against Preadtors
Most advanced featuresHollow 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 event
¨ Climate Change/Disease reason for extinction??
*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”
*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)
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 evolve¨ Alps and Himalayas Form
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