Early Earth History Origin and History of Earth

Early Earth History Origin and History of Earth and Life

Creation of the Universe • Big Bang – 13. 7 billion Years ago formed the universe • All matter originated as a dense, hot, supermassive ball with extremely high temperatures and pressures which exploded • Over Billions of years galaxies were formed including the milky way and are still expanding away from each other

Birth of Earth • Nebular Hypothesis- all bodies in the solar system formed from an enormous gas cloud composed mostly of Hydrogen and Helium • The Sun began to form at the center and contract leaving eddies which formed protoplanets and contracted into present day planets • Earth condensed into a hot liquid ball of rock and began stratification into layers according to density

Early Earth • 4. 6 Billion years ago earth took on its present day shape and position as the crust cooled and solidified • Moon formed from a collision with another large body 4. 4 BYA • Intense meteor bombardment of the surface occurred until 3. 9 BYA • Interior of Earth heated up formed Iron core, mantle material above and lightest the Crust cooled and hardened

Structure of Earth

Origin of Atmosphere and Oceans • Earths Iron core produces a magnetic field shielding earths surface from solar wind allowing an atmosphere and ocean to stabilize • Volcanic activity emitted water vapor, CO 2, Hydrogen, sulfur dioxide, methane and ammonia forming earth’s early atmosphere • Clouds of water vapor allowed cooling and rain fell forming the oceans 4 billion years ago • Acidic rain dissolved minerals into ocean, Salt

Origin of Life • Lightening, Ultraviolet radiation and heat from within the earth acted on the atmosphere and oceans causing new molecules to form, Hot smelly “primordal soup”, CHONPS • “Reducing Atmosphere” free of Oxygen is a building environment, atoms tend form bonds • Urey-Miller experiment(1952) recreated Earths early environment, 3 weeks, created organic molecules including amino acids

Urey Miller Experiment

Origin of Life • Coacervates- Bilayer phospholipid membranes form spontainously in water • Fossil Archae bacteria 3. 5 BYO found in rocks • Heterotroph Hypothesis- first organisms ate preformed organic molecules in soup • Anaeroboc respiration- fermentation and glycolysis methods of producing ATP still exist today

Energy Production • Biochemical pathways evolved from right to left, became more complex over time • Anaerobic Respiration- chemosynthesis • Anaerobic Photosynthesis- used plentiful light energy to break down Hydrogen sulfide H 2 S • Aerobic Photosynthesis- used light energy to break down water H 2 O • Aerobic Respiration- used oxygen as a final hydrogen acceptor, 32 x more energy

Oxygen and Energy • Oxygen stabilized in Earth’s atmosphere by 2 BYA as a result of aerobic photosynthesis • Oxygen was a poison to anaerobic bacteria which had to retreat underground/ mud • Ozone O 3 formed in the atmosphere which shielded the Earth from ultraviolet radiation • Respiration and photosynthesis evolved using the same structures, photo by day, resp at night. Plastids and mitochondria evolved

Mitochondria Plastids

Stromatolites Archeaozoic Eon

Multicellular Life and Symbiosis • Procaryote- single cell with no nucleus and no internal membranes • Eucaryote- contain membrane bound nuclei and organelles (some double membrane) • Eucaryotes evolved from Archae and Eubacteria combining in symbiotic relationships • By 1 BYA diverse protists were abundant • . 9 BYA multicellular organisms evolve

Classification of Organisms

Cladogram

Evolution and Natural Selection • Evolution is the change in genes over time allowing organisms to become better adapted to live in their environment • Natural selection is the environmental conditions (temp, Rain, other organisms) that a species live under and determine who is best adapted • Favorable genes are passed from parents to offspring allowing physiological and morphological changes over generations • Sexual reproduction powers evolution

Life on Earth Bacteria- Protista- multicellular organisms Sponges (porifera)First multicellular- colonial division of labor true multicellular cells specialized into tissues Jellyfish (cnidaria)- gastrovascular cavity (one opening, two way digestive tract), - nerve net(no brain) - muscles • • •

Soft Bodied Worms • Flat Worms (platyhelminthes)-Acoelomate, no body cavity • cephalization-thickening of the nerve cord at the anterior end(brain in the front) • Sense organs concentrated at front, close to brain • Bilateral symmetry-paired organs • gastrovascular cavity, one opening, two way digestive tract • eyespots

Soft Bodied Worms • Round worms (nematoda) pseudocoelomates have a body cavity but no mesentery, fluid filled • Tube in a tube body structure • One way digestive tract, two openings • Separate mouth and anus • Cephalization with ventral nerve cord • Bilateral symmetry

Flatworms Roundworms

Segmented Worms • Segmented worms (Annelida) Coelomatestrue body cavity with mesentery lining cavity and positioning organs, - Bilateral symmetry - cephalization with ventral nerve cord - Tube in a tube one way digestive tract - Metamerism- body cavity divided internally - Tagmatization- specialization of function

Segmented Worms Annelida

Hard Shelled Organisms • Molluscs (calcium Carbonate shells)-Chitons, snails, clams, oysters, Slugs, octopus and squid • Segmented worm with a shell, • protection but heavy • Muscles have solid attachment and base to pull from • Heavy shell slow movement, some lost shell to move faster, swim

Chiton Clam

Hard Shelled organisms • Arthropods- Chitin exoskeleton, very complex sugar - Strong and lightweight - protection and attachment for muscles • Millipedes-one of the first insects, two legs per segment - Legs evolved into Antennae, jaws, gills, swimmerets, stingers and egg depositors - Trilobites-survived from 500 MYA to 245 MYA

Millipede

Trilobites

Chordata • Jawless fish Lancelets and Lampreys- cartilage skeletons • Armored Fish-Placoderms, development of scales for flexibility, swimming. Large plates covering head for protection • Chondricthyes- Cartilage fish, Sharks, Rays and Chimeras, two chambered heart • Ctenoid Fish- modern day Bony fish, two chambered heart

Dunkleosteus

Armored Fish

Armored Freshwater Fish

Invasion of the land • Lobe finned Fish- had muscular limbs with ray fin tip, Coelacanth- still survives today, Indian ocean • Lung Fish- live in areas with monsoon season or very warm shallow water( hot water holds little oxygen) • Eusthenopteron- fresh water lobe finned fish from Devonian and Carboniferous periods, had gills and lungs

Coelacanth

Evolution of Tetrapods

Evolution of Tetrapods

Limb Evolution Fish to Tetrapods

Reptiles and Amphibians • Reptiles evolved from fish with scales, developed a calcium carbonate shelled amniotic egg to completely free themselves from water, Peg teeth same as fish • Amphibians had fish ancestors, develop initially with gills and fins which most loose as adults and develop lungs and legs, Eggs must be laid in water to prevent dessication

Mammals and Birds Synapsida reptile lineage led to mammals Monotremes-egg laying mammals Marsupials-pouched mammals Placental- all modern mammals, milk Diapsid reptile lineage led to Birds, close relatives of dinosaurs - Shelled eggs, scales on legs, no teeth - Archaeopteryx-peg teeth, claws on wings, 140 myo fossil • •

Synapsid

Jaws to Ears in Mammals

Archaeopteryx Fossil

Archaeopteryx

Evolution • Change in organisms over time by natural selection to better fit the environment • Every organism has the potential to produce more offspring than are able to survive • No two offspring are alike • Those individuals that posses superior traits or attributes are more likely to survive and pass on these traits • Favorable characteristics will increase in the population and gradually change the species

Evolution • Gradualism- evolutionary change occurs slowly over a long period of time • Punctuated Equilibria- evolution occurs in spurts between which there can be long periods with little change • Sexual Reproduction is the driving force behind evolution by increasing genetic diversity

Mass Extinctions • There have been 5 major mass extinctions and many more minor extinctions which cause the “punctuation” in the evolutionary record • Plate tectonics affect nearly everything that happens on the earths surface • Permian period end “Great Dying” 95% of organisms on earth extinct 250 mya • Volcanism dominated the last million years of the permian period

Mass Extinctions • Siberian Trapps- Basalt deposited over area size of U. S. • Immense amounts of CO 2 released into atmosphere over 1000 ppm Global Warming • Carboniferous coal deposits ignited adding more CO 2 and sulfur dioxide • Acid rain produced by sulfur and water = sulfuric acid

Mass Extinctions • Global warming caused ocean temperatures to rise melting deep sea deposits of frozen methane= 20 x effect of CO 2 green house gas • Global Warming caused ocean circulation patterns to slow or stop decreasing O 2 in water creating “dead zones” • Atmospheric Gases caused Ozone depletion allowing more UV radiation to reach surface • Pangea formed all continents together, large dry interior few shallow coasts • Conditions lasted for 50 thousand years

Cretaceous Tertiary Extinction • 65 million years ago, 80% extinction • Breakup of Africa and India caused massive basalt flow, increase in CO 2 levels • Deccan traps 200, 000 square mile 6, 500 ft thick volcanic deposit • Meteor 6 miles wide hit edge of Yucatan peninsular • Impact crater ejected massive dust blocked sunlight for several years(irridium layer)