Exam 3

Paleozoic Fossil Record

-In Paleozoic rocks, we find abundant fossils of multicellular organisms bearing shells -much improved at the beginning of Paleozoic strata -The pace of evolution appears to have quickened in the Paleozoic

Sauropods

"long necks" Brachiosaurus and seismosaurus

Paleozoic Paleogeography

-"ancient geography" -ancient geographic arrangement of the continents -reconstructing the paleogeography requires paleomagnetic, paleoclimatic, geochronologic, tectonic, sedimentologic, and biogeographic fossil data

Chesapeake Bay Impact Crater

-35 mya -Chesapeake Bay was struck by a 3-5 km diameter asteroid -Chesapeake Bay Crater (presently buried)

Paleogeography and Plate tectonics-Eocene

-50 mya -Antartica and Australia are connected -India not yet collided with Asia -North and South America not yet connected -South America connected or nearly connected with Antartica

K-T Extinction

-75% of all species died -Effects of the Chicxulub impact: -dust cloud that blocked sunlight for a year (bad for plants) -put sulfuric acid aerosols into atmosphere (10 years to fall out of the atmosphere, acid rain) -fire ball from impact (high O2 levels in cretaceous=mass fires, O2 levels dropped in Paleogene as a result) -100 teratons of TNT-1 billion X worse than a bomb -Tsunami that reached Missouri

Pennsylvanian Paleogeography

-Appalachian mountains have formed as a result of Alleghanian orogeny -coal swamps formed along the western edge of the Appalachian mountains in what was basically a tropical rain forest setting

Proterozoic atmosphere

-Atmospheric Oxygen skyrocketed 2.4 to 2.2 Ga. -Currently O2 is 21% of atmosphere -Before 2.2 Ga, no O2 -Redbeds (red from Fe-oxides) don't appear before 2.2 Ga

Pangea

-By Late Carboniferous, a large continental landmass had formed by the collision of Euramerica with Gondwana (the southern continents of Africa, Australia, Antartica, India, South America)

cretaceous chalk

-Chalk, a variety of limestone composed of microscopic shells (called coccoliths) of golden brown algae, was deposited in many places around the world -The word is derived from Latin word creta

Phylum Mollusca

-Clams, Oysters, Snails, Slugs, Nautilus, squid, octopus, cuttlefish -Name means soft-bodied -Cambrian to present

Alleghanian Orogeny

-During Late Paleozoic, northwestern Africa collided with southeastern North America building Appalachian mountains -the orogeny began during Mississippian and continued through Pennsylvanian and Permian

Permian Paleogeography

-During Permian, the continents continued to form Pangea -Pangea was surrounded by a huge ocean called Panthalassa -The oceanic area east of Pangea and between Africa and Europe was called the Tethys Sea -The eastern 2/3 of North America consisted of lowlands, undergoing erosion -Continental red beds were deposited locally -Subduction and volcanism continue in the far west

Triassic of Eastern North America

-During Triassic, Appalachian mountain ranges were much higher than they are today -the mountains were already eroding at the beginning of the Mesozoic

Devonian Paleogeography

-Exotic terrain called Avalon terrain collided with eastern North America in the Acadian orogeny -The Acadian highlands -Erosion of these mountains resulted in deposition of the catskill red beds in the Appalachian area

Quarternary divided into 2 epochs

-Holocene (the current epoch) -Pleistocene

Mississippian Paleogeography

-Landmass in eastern North America and Europe formed as the mountains eroded after the Acadian orogeny -Much of North America was covered by a shallow epicontinental sea -North America sat on the equator, temps were warm

Cambrian Paleogeography

-Laurentia nearly covered by shallow epicontinental seas -Laurentia lies on the equator-water is warm -Deposition of sand and carbonate sediments -water deepens toward edges of continent, where shale is deposited

Atlantic coastal Plain

-Marine and deltaic sediments accumulated gradually building a wedge of sediments that thickened seaward -This caused the ___ ____ ____ to be pushed down (subside)

Phylum Brachiopoda

-Name means arm + foot -Chief characteristics (bivalved or two shells each with bilateral symmetry. The plane of symmetry passes through center of each shell or valve) -Cambrian to recent (Abundant in Paleozoic, only few species remain today)

Proterozoic Eon

-Named before Archean life was discovered -~2 Ga (2.5 to 0.542 Ga); almost half of earth history -The unfamiliar Archean world became like today's earth -New continental crust formed but at slower rates -90% of Earth's continental crust by middle of this eon -Continents grew by addition of volcanic arcs and hot spots (middle of tectonic plate)

Petrified Forest

-National Park in Arizona has fossilized logs of trees -occurred in Triassic -Formed by permineralization -Quartz crystallized in pore spaces of wood -Actual woody part eventually dissolves away

Ordovician Paleogeography

-Note the mountains and volcanoes in the Appalachian regions -Volcanic ash deposits are found in ___ rocks throughout the Eastern US

Paleogene divided into 2 epochs

-Oligocene (youngest) -Eocene -Paleocene (oldest)

Paleozoic Paleoclimates

-Paleoclimatic evidence comes from environmentally-sensitive sedimentary rocks (glacial deposits, coal swamp, reef, carbonates, evaporites) -Early paleozoic climate was affected by: -The Earth spun faster and had shorter days -Tidal effects were stronger because the moon was closer to Earth (high tide was high and low tide was low) -No vascular plants were present on the land

Pleistocene Ice Age

-Pleistocene began 1.8 mya -5 glacial pulses -last ice age hit its max at 18,000 years ago -sea level dropped as much as 75 m -polar ice has been melting since -this coincides with a rise in sea level

Neogene divided into 2 epochs

-Pliocene -Miocene (oldest)

The Breakup

-Rifting and volcanism during Triassic, resulting in the separation of Eurasia from Gondwana -Intrusion of dikes and lava flows in eastern North America -Atlantic ocean opened and widened -rifting and separation of Africa, India, and Antartica (in the process, large volumes of Basalt were extruded) -South America began to split from Africa by late Jurassic and completely separated by late cretaceous -India was moving northward toward Asia -The total time for the fragmentation of pangea was about 150 million years

Corals

-Scleractinian corals appeared during Triassic -became dominant coral we see today

Banded Iron Formations (BIFs)

-Sedimentary rocks greater than 15% Fe -consisting of alternating layers of Fe-rich minerals and chert -Algae now produced O2 -Discovered iron entered the ocean from weathering and submarine volcanic activity and reacted with dissolved oxygen to form hematite and magnetite -No longer forming on earth, too much O2 now

Iaptetus ocean closed

-The Iapetus ocean completely closed by Late Carboniferous -Closure disrupted global ocean circulation and caused currents to be diverted from the tropics to more polar areas, contributing to glaciation

Ordovician Orogenies

-The Taconic orogenic belt lay between Laurentia (N. America) and Baltica (Europe and western Russia) during ___. -Plate tectonic cross-sections showing forces and movements that caused the Taconic Orogeny

Paleozoic Plants

-The first primitive land plants appeared near end of Ordovician -Vascular plants expanded across the land, forming great forests during Devonian -The plants progressed from seedless, spore-bearing plants to plants with seeds but no flowers (gymnosperms)

Pangea on the south pole

-The supercontinent was located at and around the south pole -When conditions are right for a glaciation, if the climate is cold and if sufficient moisture is present

Taconic Orogeny

-Volcanic island arc collides with eastern N. America. -As the Iapetus ocean narrowed, a volcanic island arc approached and collided with North America causing folding, faulting, metamorphism, and mountain-building -480-460 Ma

Neoproterozoic Paleogeography

-When continents are located on a pole and if other conditions are right, glaciers tend to form. During glaciations, sea level is lowered worldwide because the water is tie up in the ice sheets. Just before the Paleozoic began, the Precambrian supercontinent Pannotia, had begun rifting apart and six large continents and several smaller continents resulted.

cephalopods

-ammonoids (the dominant swimming invertebrates in Mesozoic seas, very abundant during Mesozoic) -the geologic range of ammonoid is Devonian to cretaceous -distinct suture patterns (suture=framework of shell)

Coccolithophorids

-appeared during early Jurassic -abundant during cretaceous-formed extensive chalk deposits (white cliffs of dover)

Newark Supergroup

-basins filled with sediments eroded from the Appalachians -Basaltic lava flows and intrusions (sills and dikes) -Records the break up of Pangea between North America and Africa

Archaeopteryx

-best known bird fossil, which was first to be discovered, although perhaps not the oldest -the word means "ancient wing" -feathers=thinner than modern birds -wings=mainly gliding

Subphylum Trilobita

-body has 3 lobes -Cambrian to permian

Orogenic belts

-present along the edges of the continent -strata are intensely deformed with folding, faulting, metamorphism, and igneous intrusions -Deformation occurred as a result of continental collision

Antartica and Australia separate

-circumpolar currents isolated Antartica from warmer waters (led to cooling of Antartica) -cold dense ocean waters around Antartica drifted northward along ocean floor, contributing to global cooling and the ice age

Why the Cambrian explosion?

-climate conditions became more favorable after the end of the late-proterozoic glaciation -Perhaps the glaciation produced an extinction event in the Pre-Cambrian animals -Extinction events of the Phanerozoic have been followed by rapid proliferation (reproduction, evolution)

Alps and Himalayas

-collision of Africa and India with Eurasia forming mountains -Tethys Sea deposits were deformed into mountain ranges -these mountains are made of marine sediments

Proterozoic orogenic events

-continental collision created Precambrian supercontinents -Rodina- formed ~1 Ga -The Greenville orogeny formed an extensive mountain belt -Pannotia- A short-lived supercontinent ~600 Ma

mososaurs

-cretaceous only -up to 50 ft long (15 m) -probably top predators

Red Sea

-divergent plate boundary -rifting occurred between Africa and Arabia, forming the __ __ and Gulf of Aden -about 30 mya

Reptiles

-diverse during Mesozoic -many new groups appeared including the ancestors of the turtles, and many types of marine reptiles -evolved from amphibians -some were successful in readapting to the marine environment -reptiles originally developed adaptations so they could live on dry land without returning to the aquatic environment for reproduction -went back to the ocean for food

Molluscs

-diversified following permian extinctions, and became more diverse than during Paleozoic -surpassed the brachiopods (which dominated the Paleozoic seafloor)

sea turtles

-evolved during cretaceous

Rise of Mammals

-evolved during late Triassic -early mammals rodent-like, and remained small throughout Mesozoic -warm-bodied, distinctive because have hair or fur and females have mammary glands that secrete milk to feed young 1. Monotremes-primitive mammals that lay eggs, included duck-billed platypus 2. Marsupials-carry young in pouches (opossums and Kangaroos) 3. Placentals-the young are retained longer within the mother's body and highly developed placenta present

Ornithischian dinosaurs

-evolved near end of Triassic -bird hipped, pelvic structure resembles that of modern bird -includes both 2 legged and 4 legged types -all herbivores -front legs shorter -Triceratops and Stegosaurs (plates on back served to regulate temperature)

Pleslosaurs

-fed on fish using slender curved teeth -short broad body and extraordinarily long neck with small head -up to 12 m long -large, many-boned, paddle-like limbs

Fish

-first fish no jaws -fish appear in cambrian -jaws evolve in Late Silurian -Lungfish (Late Devonian) evolve muscular fins to walk on bottom of water body and primitive lungs

Plants

-first plats spore-bearing (mosses and ferns) -wood evolves Middle Devonian -seeds appear Late Devonian -Trees appear Late Devonian

Sierra Nevada Mountains

-formed as a batholith (blob of magma) -tectonic plate subducted under North America during Mesozoic -Paleogene erosion removed overlying rock (exposed this gigantic batholith) -Yosemite National Park

Rocky mountains

-formed in New Mexico, Colorado, and Wyoming during the Laramide orgoeny at the end of the cretaceous -This drained the western interior seaway

dinosaurs

-greek "terrifying lizard" -appeared during late Triassic, about 230 mya -earliest were small (many less than 1 m long) and both carnivores and herbivores -they become much larger later during Jurassic and cretaceous

ornithischians

-group of dinosaurs -bird-hipped

Cretaceous Paleogeography

-high sea level and vast epicontinental seas -Western interior seaway forms (connects Arctic ocean to Gulf of Mexico)

Phylum Anthropoda

-insects, spiders, shrimp, crabs, lobsters, trilobites, barnacles, ostracodes, eurypterids -name means jointed + foot -Cambrian to present

Cambrian diversification

-known as the "Cambrian explosion" -Abrupt appearance of many types of animals about 535 million years ago, followed by rapid evolution -During that, all major invertebrate phyla appeared in the fossil record (except Bryozoa)

Saurischian dinosaurs

-lizard hipped -pelvic structure like lizards -both herbivores and carnivores -teeth adapted to cutting and tearing but not chewing -food was ground up in the gizzard, probably aided by stones the dinosaurs swallowed called gastroliths

Mass Extinctions of Paleozoic

-many of the geologic periods of Paleozoic began with times of rapid evolution of organisms -Several of the Paleozoic periods ended with extinction events -Late ordovician, late devonian, end of permian (most catastrophic mass extinction in history of life)

Phylum Bryozoa

-may resemble lace or a tiny net -may be delicately branches -finger-like, circular, or dome-shaped -Ordovician to Present

Flying Pterosaurs

-means "winged lizard" -earliest flying reptiles were probably gliders -later forms were active fliers, with flapping wings, rather than gliders -Quetzalcoatlus- 15 m wingspan largest flying vertebrate

Paleozoic invertebrates

-most major invertebrate phyla were present during Paleozoic including sponges, corals, bryozoans, brachiopods, mollusks, anthropods and echinoderms -almost all common invertebrate phyla in existence had appeared by Ordovician

Moraine

-pile of sediment resulting from glacial movement -terminal moraine=furthest extent of glacial growth

gastropods

-predatory gastropods appeared during cretaceous -drill circular holes in shells in order to eat the soft parts -new mode of predation not seen before -a common living example of a carnivorous gastropod is the moon snail

Amniotic egg

-provided freedom from dependency on water bodies -Helped vertebrate live in diverse types of terrestrial environments -important milestone in the evolution of vertebrates

The Age of reptiles

-reptiles inhabited land, sea, and air -dinosaurs appeared during Triassic and were the dominant land vertebrates until the end of cretaceous -mammals first appeared during the Triassic. Early mammals=rodent-like -The earliest bird appeared during Jurassic -Flowering plants or angiosperms first appeared during early cretaceous and become dominant to today

Phylum Echinodermata

-starfish, sea urchins, sand dollars, crinoids -Name means spiny + skin -Cambrian to present

Holocene

-started ~10,000 years ago -we are still in an ice age -right now is considered an interglacial period

The breakup of Pangea

-the Northern continents are called Eurasia and the southern continents are called Gondwana -As North America and Gondwana separated, they were called Laurentia and Baltica

land plants

-the angiosperms or flowering plants made appearance during cretaceous -Angiosperms diversified while the gymnosperms declined during late cretaceous

Burgess Shale

-the extraordinary well-preserved __ ___ of Canada provides a window into the past to view the spectacular diversity of the Middle Cambrian -Many soft-bodied organisms are preserved in black shale, along with soft parts of animals with shale

Devonian Sedimentary deposits

-the red color of the sandstone indicates deposition under oxidizing conditions in continental or non-marine environments.

San Andreas Fault

-turns on -North America came in contact with NW moving Pacific Plate

Colorado Plateau

-uplift occurred during Pliocene -This uplift ultimately rejuvenated (more energy) the Colorado River -Formed the Grand Canyon

Birds

-warm-bodied, wings, feathers, lay eggs, most can fly, some flightless -bones=hollow and not easily preserved -birds may have evolved from small triassic therapod dinosaurs -several theropod dinosaurs had feathers and hollow bones -feathers evolved from reptilian scales -earliest feathers have been used for insulation, camouflage, or display, rather than flight

Epicontinental Seas

-wave-washed sands, muds, and carbonates were deposited in the shallow ___ -sites of major diversification of marine life

Triassic-Jurassic extinction

200 mya -70-75% of all species died -New study suggest increased volcanic activity caused extinction

Mesozoic Era

252-66 mya "middle life" 3 periods -Triassic (252 to 201 mya) -Jurassic (201 to 145 mya) -Cretaceous (145 to 66 mya) -began after the Permian-Triassic extinction event -Mesozoic fossils are more advanced than those of Paleozoic, but not as complex as those living today -New vertebrates-birds and mammals -ended with extinction event in which the dinosaurs died off

Phanerozic Eon

3 eras -Paleozoic="ancient life" (541-252 Ma) -Mesozoic="Middle life" (252-66 Ma) -Cenozoic="recent life" (66 Ma-present)

ordovician-silurian extinction

438 mya Global ice age 2nd biggest mass extinction event in earth history

Cenozoic Era

66 mya to present -"new life" or "recent life" 3 periods: -Youngest-Quarternary -Middle-Neogene -oldest-Paleogene

Class Amphibia

Amphibians -Both + life -Living a double life (water and land) -Late Devonian to present

Jurassic Paleogeography

Appalachians continue to erode Western US seas flood North America craton

Precambrian time

Archean and Proterozoic Eons comprise in interval of time informally called ???, which spans 87% of the geologic time scale

Proterozoic Eon

Atmospheric O2 now permitted diversification of life -aerobic respiration is efficient; allowed multicellular life -without O2, only single celled organisms possible -evolved by at least 1 Ga -the possibility of land dwelling biota -O2 made formation of the ozone layer possible -ozone absorbs deadly ultraviolet (UV) radiation -Life forms evolved slowly -Eukaryotes (bacteria with nuceli) evolved 2.7-2.1 Ga -Multicellular life forms appeared by 750 Ma -Large life forms leaving obviously recognizable fossils evolved ~620 Ma -Late Proterozoic life: complex, soft-bodied forms, resembled jellyfish, worms

Paleozoic

By Late Cambrian, the continents moved off the poles. Glaciers melted, sea levels rose, and shallow epicontinental seas flooded the continents.

Class Crinoidea

Crinoids -animals which resemble flowers -middle cambrian to present (Abundant in Mississippian)

Transgressions

During early Paleozoic, shallow epicontinental seas ___ onto the continent and across Laurentia continent as glaciers melted and sea level rose

cretaceous catastrophe

Evidence: -thin layer of clay with a concentration of iridium is found at boundary at the end of cretaceous (the boundary clay) -Iridium is more abundant in meteorites than in Earth rocks -purposed that a large impact of an extraterrestrial object with the Earth at the end of cretaceous might have spread iridium around the globe -180 km diameter crater on the Yucatan Peninsula Mexico of the same age as the boundary layers

Hadean Eon

Geochronology dates the age of Earth to 4.57 Ga based on the ages of meteorites. Between 4.57 and 3.8 Ga the rock record is scarce. Named for Hades, the Greek God of the underworld. Began with formation of earth by planetesimal accretion.

Orogenies

In the Appalachian region, there were 3 Paleozoic mountain-building events -Taconic -Acadian -Alleghanian

Class Hexapoda

Insects -The insects are among the most diverse living group on earth but they are rarely found as fossils -Devonian to present

Snowball Earth

Late proterozoic -major climate shifts -Glaciers covered continents, ocean surface frozen -many life form probably became extinct as ocean chemistry and photochemistry changed due to ice cover -CO2 from volcanism warmed Earth, ended major ice age

Where did life originate?

Life probably began in the sea, hydrothermal vents or black smokers. Microbes at the vents are hydrothermophiles that thrive in seawater hotter than boiling point (100 degrees Celsius). These microbes derive energy by chemosynthesis, without light, rather than by photosynthesis (suggests origin in deep water in absence of light)

Laurentia

North America, Greenland, Ireland, Scotland

Class Reptilia

Reptilus -means creeping complete colonization of land -Pennsylvania to present

Formation of the Moon

Soon after the differentiation, Earth collided with a proto-planet the size of Mars. This planet blasted away a sizable chunk of Earth's mantle and part of the proto-planet's mantle. The impact further melted the remaining mantle. Debris from the collision formed a ring around Earth.

Miller Experiment

Stanley Miller stimulated early atmospheric conditions (H2, CH4, NH3, H2O, electrical sparks to stimulate lightning), first laboratory synthesis of amino acids

Archean Life

Stromatolites: -First large fossil structures-layered mounds of sediment -Alternating layers of cyanobacteria and sediment settling from water -first appear ~3.2 Ga -photosynthesis changed Earth's atmosphere

Painted Desert

The rocks of this in Arizona form in Triassic

Regressions

The seas __ as the glaciers enlarged and sea level dropped

Theropods

Tyrannosaurus and Velociraptor

Hadean Eon

Why are there no rocks on Earth older than 4.03 Ga? Massive bombardment of Earth and its moon by meteorites. 4.0-3.85 Ga, destroyed nearly all of Earth's surface. Late heavy bombardment

North and South America join

at Panama -land bridge between N. and S. America (pathway for plant and animal migration) -causes gulf stream to flow like it does today (warms western Europe)

Phylum Cnidaria

corals, sea fans, jellyfish, and sea anemones -Name: named for stinging cells called Cnidoblasts or Cnidocytes -Late Pre-Cambrian to Present

Hadean atmosphere

different from ours. Early atmosphere was denser. Probably formed by "outgassing" from volcanism. Colliding comets may have added gases. Humans would not have survived. There was no free oxygen and no evidence of oxidation from this time.

crocodiles

evolved during Triassic as terrestrial animals

Paleozoic Vertebrates

fish, amphibians, reptiles, synapsids (mammal-like reptiles) -the first vertebrates were jawless fish, which are found in rocks as old as cambrian in China -Fish with primitive lungs gave rise to the 4 legged animals or tetrapods -The transition from water-dwelling vertebrates to land-dwelling depended on the evolution of the amniotic egg

Archean Eon

from 3.85 to 2.5 Ga Based on first abundance of crystal rocks (3.85 Ga) Plate tectonics begins during or just before End of the Eon, continental crust reached ~85% of present area The 1st cratons had formed by 2.7 Ga. Cratons are long-lived blocks of durable continental crust. They are too buoyant to subduct so these blocks persist over time. Cratons are the interior core of modern continents. Continents grow as rocks are added to cratons. The 1st oceans formed as rain from the skies (liquid water required cooling of the surface, first evidence of oceans from marine sediments ~3.8 Ga) Earliest evidence of life (earliest organisms developed in atmosphere lacking oxygen, anaerobic conditions, No oxygen=no ozone so the earth hit with UV radiation), UV radiation and lightning recombines water, ammonia, and hydrocarbons to form amino acids

Saurischians

group of dinosaurs lizard-hipped ***Birds actually evolved from theropods

Earth began to heat up as it grew larger via...

kinetic energy from meteorite impacts, gravitational compression, and radioactive decay. Earth became hot enough to partially melt by ~4.5 Ga. The molten Earth underwent chemical differentiation. Gravity pulled molten iron into the center. The ultramafic mantle remained as a thick shell.

Phylum Chordata

means string referring to nerve cord and or notochord

late devonian mass extinction

mostly involved marine life uncertain about cause (oceanic volcanic activity? extraterrestrial impacts?) 50% of life died

Silurian Paleogeography

mountains in eastern North America are eroding. Sandstone and conglomerate deposits

Bivalves

oysters were among the most successful

Class Asteroidea

starfish -star shaped Ordovician -5 arms

permian-triassic extinction

the great dying 252 mya 90-96% of all species died theories include impacts, increased volcanic activity, and release of methane hydrates from the ocean

Phylum Porifera

the sponges -name means "pore-bearing" or covered by tiny pores -Precambrian to Present

2 types of saurischian dinosaurs

theropods: bipedal carnivorous dinosaurs Sauropods: large quadrupedal herbivorous dinosaurs