ETT Final Exam

Cretaceous Period

(145 to 66 million years ago) Paleogeography: -Mowry Sea (turns into...) -Western Interior Seaway in North America: -Separates into two parts −Important for fossil record in this region -Ocean currents: -Continents splitting apart affects currents and climate −Tethys Seaway Climate: -Warm temperatures at high latitudes (dinosaurs found near South Pole) -Cooling of the poles begins in the Late Cretaceous but dinosuars still find a way to adapt to cool temperatures Cretaceous Invertebrates: -Similar to Jurassic -Plankton (zooplankton and phytoplankton) move toward more modern forms -Radiations of various microorganisms (Diatoms, Foraminifera) -Cephalopods continue to radiate (ammonoids, belemnoids) -Other groups diversify: -Bryozoans (encrusting forms) -Burrowing bivalves (mollusks) -Gastropods (mollusks) -Decapods (crabs) -Rudist bivalves (Helped form reefs, Up to at least 1 meter tall) -Reduction of some groups: -Brachiopods -Stalked crinoids -Crinoids still exist today in different free-swimming forms - insects-->begin to co-evolve with flowers and flowering plants, often as pollinators Cretaceous Plants -Gymnosperms are still present and diverse -Angiosperms first appear--increase in diversity (Flowering plants, Hardwood trees with better nutritional content in leaves) -Increases in complexity and form Cretaceous Vertebrates- many groups are similar but several changes Fishes: -Teleost fishes: -Most dominant modern group -Specialized ray-fins symmetrical tails, short jaws (control of what you eat) -Make them better suited for evolving environment -*Suction feeding to eat—this is why they do better than other fish!* Marine reptiles: -Still important parts of the ecosystem -Still includes plesiosaurs, Pliosaurs, ichthyosaurs -Newer groups include: −Marine turtles- some got large −Aquatic/marine birds- legs rotated, harder to move on land -Mosasaurs-Relatives of lizards, At least 15 meters long -Crocodilians: Continue to get larger, Become dominant predators -Dinosaurs: Continue to be dominant terrestrial vertebrates, Most Early Cretaceous forms are similar to those from the Late Jurassic -Different dinosaur groups begin to dominate in the Late Cretaceous: -Iguanodonts- First show up in Early Cretaceous, Early members of the Ornithopoda--This group eventually becomes some of the most numerous dinosaurs throughout the Cretaceous -Hadrosaurs ("Cows of the Cretaceous") Evolve from ornithopods, Herbivores, Common by the Late Cretaceous -Ankylosaurs (Armored, quadrupedal herbivores, Some possessed tail clubs) −Pachycephalosaurids (bone-headed dinosaurs)--Small, bipedal −Ceratopsids--Frilled dinosaurs that often have 1 or more horns, Quadrupedal herbivores -Titanosaurs (e.g. Dreadnoughtus)--Members of the Sauropods, Last and potentially largest members, Found nearly worldwide (North and South America, Europe, Africa, Asia, and Australia) -Abelisaurs: theropod, Bipedal carnivores from Gondwana (southern continents), Short heads, very reduced forelimbs/arms −Dromaesaurids (raptors)- theropod Bipedal carnivores, Swift, agile, relatively small predators, Evidence of feathers −Tyrannosaurids (e.g. Trex) -Largest terrestrial predators ever, Bipedal carnivores, Evidence of feathers in member found in China Mammals: -Most stay small, rodent-like -Evolving: larger brains, different tooth types, larger body sizes (relative) -Differentiation: −Eutheria-placental mammals: more mature offspring −Metatheria-marsupial mammals: tiny and more immature offspring −Monotremata-monotremes: egg-laying mammals Orogenic Events -Laramide Orogeny- what creates the Rocky Mountain -Late Cretaceous -Kula plate subducted under North American plate -Alpine Orogeny- what creates the Alps -Cretaceous into Cenozoic -Collision of African and Arabian plates with Eurasian plate (Africa and Middle East with Europe) "India's Run to Freedom": -India separates from Africa -Begins in the Late Cretaceous (~80 million years ago) -Movement started at about 18-20 cm per year (very fast) -Slowed to about 4.5 cm a per year in Paleocene around 55 million years ago (still fast) -Collides with Asia about 10 million years ago

Triassic Period

(251 to 200 million years ago) Geographically, Pangea is in still in existence Sea use expansion of pelagic: Pelagic (refers to area in water above the sea floor) -Dinoflagellates -Calcareous nannofossils -Cephalopods -Ammonoids -Belemnoids

The Evolution of the Eukaryotic Cell

*some bacteria gave rise to chloroplasts and some bacteria gave rise to mitochondria Plant-like eukaryotes evolved as a result of a second union of 2 kinds of cells. -Immobile precursor cells evolved into immobile photosynthetic forms, while mobile precursor cells evolved into mobile photosynthetic forms. -aerobic prokaryote--they have nuclei but live without oxygen and lack mitochondria, obtaining energy directly from their hosts *before they could develop the habit of eating prokaryotic cells, including the cell that became the mitochondrion, they had to evolve the cytoskeleton (absent in prokaryotes)--a set of fibers that underlie the outer membrane of the cell and allow the cell to change its shape for various purposes *the earliest-evolving living eukaryotes exist as parasites in animals. Bacteria and Archaea= prokaryotes w prokaryotic cells Prokaryotes= Bacteria and Cyanobacteria Single-celled eukaryotes: *mitochondrion develops to allow cells to derive energy from food through respiration *chloroplasts develops as the site of photosynthesis in eukaryotes *evidence for phagocytosis: the engulfment of large particles by a cell is the presence of DNA different from the DNA in the nucleus multi-cellular life: animals and plants

Silurian diversity recovery

-60% of marine invertebrates lost -trilobites do not recover -new niches aren't made: reinvade old niches -brachiopods, bivalves, graphtolites diversify

Reduction-oxidation reactions (Redox)

the chemistry of life Chemical reactions that transfer electrons between reactants

Convergence

unrelated animals or plants evolve into similar forms, often due to similar conditions and environments which require similar behaviors ex: Ichthyosaurs ("fish lizards") −Fusiform (streamlined, torpedo-shaped -Look very similar to modern day dolphins but are very different

4th Mass Extinction: End Triassic

~201 million years ago 4th mass extinction -Happens quickly -35% of marine genera go extinct -At least 50% of total species went extinct -Conodonts disappear -All non-dinosaur and non-crocodile archosaurs go extinct Reasons: -Pangaea is splitting end of Triassic increased volcanic activity, particularly in the Atlantic region -release of a lot of greenhouse gases climate change -Asteroid impact has also been suggested (probably not correct)

5th Mass Extinction: End-Cretaceous

~75-80% of life went extinct (about 66 million years ago) -Dinosaurs -Ammonoids -Mosasaurs and other marine reptiles -Pterosaurs -Reductions in gymnosperms and angiosperms -90% calcareous nannoplankton and foraminifera went extinct -Meteor impact -Iridium anomaly -Volcanic events -Walter and Luis Alvarez discovered an iridium layer, which suggested extraterrestrial impact (asteroid), at the same time as animals dying out 66 million years ago -Other evidence −Large crater on Yucatan Peninsula −Microspherules −Shocked quartz -Deccan Traps in India: -Igneous material seeping up that are toxic and creating conditions that animals cannot tolerate -Very active at the end of the Cretaceous and at the time of extinction No more dinosaurs... Paleogene= age of mammals (and birds) in Cenozoic Era

Carbon cycle: positive feedbacks

Positive feedbacks- accelerate global warming With increasing temperature: 1) Ice albedo (reflection) decreases *ice reflects light/heat from the sun well *darker waters absorb light/heat from the sun and increase warming 2) Oceanic gas release (CO2) increases *This feedback explains why CO2 can lag temperature during periods of glaciation- the mechanism controlling glacial/interglacial periods is the Milankovitch Cycles, meaning that progression through these cycles initiate warming which causes CO2 to escape from the ocean back into the atmosphere, which further accelerates warming. 90% of the geologic record shows CO2 leading temperature. 3) Methane release increases *Methane hydrates, found on both the ocean floor and in permafrosts are primarily stable at low temperatuers and high pressures. Increasing ocean temperatures release methane hydrates in the ocean floor 4) Wildfires/desertification increases *Burns carbon based plants and releases CO2 and reduction to primary production *Deserts often cant support abundant life resulting in less primary production

Terrestrial Locomotion

Sprawling- not fast nor agile Erect: dinosaurs/mammals; helps with agility Pillar-erect- too narrow; no control

Stromolites through time

Stromatolite= layered rocks that form when certain prokaryotes bind thin films of sediment together less abundant and more restricted in occurrence pre-cambrian stromatolites: -Wopmay orogen, Canada -commonly grew in subtidal settings Early Paleozoic thrombolite: -cambrian forms were largely confined to the intertidal zone. -this restriction probably resulted from the effects of newly evolved grazing animals (including mollusks) Modern stromatolites: -modern forms largely confined to the intertidal zone -in modern seas, relatively few kinds of organisms can tolerate the unstable temperatures and salinities of the intertidal zone *presumably even fewer animals occupied this hostile environment during the cambrian *even so, cambrian structure are riddled with holes made by animals (aka thrombolites)

Rodinia

Supercontinent 1 billion years ago Rift between Laurentia, and Australia/Antartica will create the pacific ocean--most significant rigting event of all time (~700-800 million years ago) -Grenville and contemporaneous orogenic belts-- the final event to expand the continent, which ended about 1 billion years ago Another super continent? 550 million years ago -pan African and contemporaneous orogenic belts

Moving to land requires changes to

Taxa -respiration -reproduction -feeding -desiccation (drying out) -gravity v buoyancy

Microbes

The "unseen majority of life" -numerous (Human population= 7x10^9, Microbial population= 5x10^30) -phylogenetically diverse -metabolically diverse -ubiquitous

The story of early paleozoic biotas

is essentially a story of life in the sea. The oldest organic reefs with skeletal frameworks formed in Early Cambrian time. -there were suspension feeders like the eocrinoid -abundant since their skeletal plates are the principal components of many Cambrian limestones -Acritarchs are through tot have persisted as important members of the phyotoplankton and the archaeocyathids: -suspension feeder that pumped water through vase shaped and bowl shaped skeletons -probably sponges. -became extinct at the end of the early cambrian

Stromatolite

layered rocks that form when certain prokaryotes bind thin films of sediment together

3 major groups of bilaterally symmetric animals

lophotrochozoans: a diverse, ancestral group; the most familiar of which are the molluscs and the annelids (segmented worms) ecdysiozoans: many members of this group regularly shed their cuticle, a process called ecdysis. Segmented form appears to be a soft bodied arthropod or close relative of arthropods. deuterostomes: group that includes humans. Appearance of an echinoderm except in having threefold symmetry instead of fivefold symmetry.

Spores

Devonian -tiny durable structures adapted for dispersal outside the plant -spore grow into tiny egg and sperm bearing generations -sperm and egg produce adult plant *sperm still require through film of water to the egg, Ferns are still tied to moist environment*

Reorganization of faunas due to pulse of warming

-A small amount of greenhouse warming from an initial release of methane would have led to further melting of methane hydrates and further warming in early Eocene BUT greenhouse warming would have weakened in a few years as the methane added to Earth's atmosphere oxidized to CO2 habitat changes associated with vegetation changes -Mammalian Great Migration from Siberia to Alaska (via a land bridge that is flooded today by the Bering Sea) -Primates, odd-toed ungulates, even-toed ungulates, members of the opossum family -*brief climatic event profoundly reorganized mammalian fauns on a global scale* Warmth extended to high latitudes -Northerly regions experienced balmy climates during the Eocene -Isotope ratios in foraminifera show that tropical seas were ~5-8 degrees Celsius warmer than today -Forests (widespread in the Eocene) contributed abundant water vapor, which also acts as a greenhouse gas

Jurassic into Cretaceous

-Atlantic Ocean getting larger -2 landmasses: one in the North and one in the South as they break apart

C4 Grasses Radiate in the Miocene

-C4 grasses radiate: -Analyses of ancient grassland soils and of teeth of herbivores that grazed on grasslands revealed a pronounced shift toward heavier carbon isotope ratios between 7 and 6 million years ago −Isotope ratio of carbon reflects the ratio in the plants that produced it −Shift reflects partial replacement of the group of grasses known as C3 grasses by C4 -More effective at converting CO2 than previous C3 grasses -When C4 grasses extract CO2 from the atmosphere, they assimilate a larger fraction of carbon 13 than C3 grasses do -Better at using 13C in their structure -Expansion of C4 grasses caused problems for grazing herbivores that lacked tall teeth--malnutrition for those animals whose teeth were worn down by grass death: large extinction in North American mammals—especially herbivores of large body sizes that lacked tall molar teeth; only grazing species whose molars were extremely tall survived -What caused this spread of C4 grasses? -Global climatic change −C3 grasses require a cool, moist growing season to flourish while C4 grasses predominate where the moist season is warm (i.e. tropical savannahs) -Coevolution with grass-grazers: −Mammals--Ungulates and Mice -Snakes -Modern birds -General cooling and drying of envrionment -Apes radiate--early human ancestor breaks off

Meteorite created the site of the Chesapeake Bay

-Chesapeake Bay is the largest estuary, broad valley drowned by the ocean, in the world -Several rivers converge in the CB to empty their waters in the Atlantic Ocean -The configuration is similar to that of some meteorite craters on the moon -Within the rubble, there are abundant shocked mineral grains resembling those found in the Cretaceous-Paleogene boundary -Similar grains occur at the same stratigraphic level of the Gulf Coast, Gulf of Mexico, and the Caribbean -Rubble was found beneath the sand and the clay -In short, there can be little doubt that the confluence of rivers developed because the crater created a slight depression that attracted drainage from the uplands to the north and the west

Carbon cycle: atmospheric and oceanic fluxes

-Conservation of mass- carbon is not created or destroyed but moves in reservoirs (i.e. fluxes) -Equilibrium vs. kinetics -Equilibrium- balance of forces/energy -Thermodynamically drive -Kinetics- rate of reactions Atmosphere and ocean are in equilibrium -Henry's law- concentration of gas in liquid proportional to pressure above ~41% of anthropogenic carbon found in the ocean Atmosphere: More CO2 results in warmer surface temperature Ocean: More CO2 results in ocean acidification

World geography of the Middle Eocene

-Early in the Paleogene Period, continents were arrange much as they are today, but they were bunched more closely together -The quick rise of global warm temperatures early in the period and the onset of cooler conditions (as well as drier conditions on land) produced widespread extinction late in the Eocene

Eccentricity

-Eccentricity (~100,000 year cycles) -How elliptical Earth's orbit is -Doesn't change the total distance; just the shape -Exaggerates climate difference between farthest point in orbit (aphelion) and closest point (perihelion)

Devonian extinction

-Glaciation event -spread of forests -depleted greenhouse gases -increased weathering -reduced atmospheric CO2

Carboniferous Paleogeography

-Gondwana has collided with Eurasia -Appalachian mountains begin forming (Alleghanian Orogeny) 2 zones: marine and freshwater Marine: -Ammonoids abundant very mobile -brachiopods rebounded, produce reefs -Shallow areas: crinoid meadows (sea lilies) -Fuslinids diversify Extensive swamps developed: -coal swamps dominated by lycopods -lepidodendron (30m tall) -sigillaria -carboniferous coal deposits -termites have not yet evolved -seed ferns evolve (Glossopteris) Upland Floras: -late Carbiniferous -gymnosperms -"naked seeds" -Coradites (100ft) -Naked seeds are exposed to the environment -Conifers and Cycads Gymnosperms -pollen (sperm) grains form on top of the cone and wind transports to another cone that has produced eggs Invertebrates: Late carboniferous many flying insects present -could not fold their wings over their bodies in Early Carboniferous -wingspans of 2.5 feet -Foldable wings, egg laying organs, mouthparts for sucking juices -Giant arthropods

Paleoclimate reconstruction

-Heavy to light isotope ratio used to constrain temperature -δ 18O concentration increases with a decrease in temperature Paleotemps reconstructed with: 1)Carbonate shelled organisms -Benthic foraminifera--Ocean temperatures -Corals/diatoms/gastropods 2) Ice cores −Lighter isotopes are preferentially evaporated--Glaciers are large reservoirs of 16O -Air bubbles trapped in ice--Atmospheric temperatures, CO2/CH4 record -Most detailed chronology of ice age glaciation comes from oxygen isotope ratios of foraminiferal skeletons preserved in deep-sea sediments -Slightly before 3 million years ago, there were marked increases in the ratio of oxygen 18 to oxygen 16 in the skeletons of foraminifera in the oceanic areas -->This change resulted from a brief episode of widespread cooling

"India's Run to Freedom"

-India separates from Africa -Begins in the Late Cretaceous (~80 million years ago) -Movement started at about 18-20 cm per year (very fast) -Slowed to about 4.5 cm a per year in Paleocene around 55 million years ago (still fast) -Collides with Asia about 10 million years ago

The Cambrian Period

-Life in the oceans diversified rapidly at the end of Proterozoic time -this diversification accelerated in what has been termed the Cambrian explosion of life -brief episodes of mass extinction also occurred during the Cambrian period -*evidence from burrowing animals: -Neoproterozoic rocks (slightly younger than 500 million years) with horizontal burrows (worm-shaped animals)--simple unbranched burrows. -older proterozoic strata are strikingly well stratified, reflecting the absence or near absence of burrowing animals -->then at the base of the Cambrian system (542 million years) there are branched burrows, reflecting an increase in behavioral complexity. They are present in rocks below those in which the earliest skeletonized fossils occur. 3 intervals of the Early Cambrian: (characterized by distinctive fauna-many of which had evolved skeletons) 1 Lowermost Cambrian: Anabarites--tube-shaped Cambrotubulus--vase-shaped Conodontomorph--tooth of a predatory animal 2 Tommotian Fauna: -First discovered in Siberia, but it is now recognized on many continents. -Contains skeletal elements that cannot be assigned to any living phylum and that show no relation to any group of fossils found in post-Cambrian rocks. -Contains the oldest known members of a few groups that survive to the present day: sponges, monoplacophorans, and brachiopods. -this fauna likely occupied the seas for 3-4 million years Large animals with skeletons -larger fauna and most belonging to phyla that survive to the present time -trilobites: most lived on the surface of sediments, some were shallow burrowers and a few kinds were small planktonic (floating) forms that must have been suspension feeders -the most abundant animal groups with skeletons that shared the late Early cambrian seafloor with trilobites were monoplacophoran mollusks, inarticulate brachiopods and a variety of echinoderms *the soft bodied Chenjiang Fuana Although ~30 million years younger than the soft bodied Ediacaran fauna, contains a very different group of soft-bodied taxa. -members: jellyfish, segmented worms, other cnidarians, arthropods that lacked mineralized skeletons (the most diverse group of the Chengjiang fauna) and priapulid worms (which survive today by way of eight species that feed on other worms)

The Eocene started with a pulse of warming

-Marking the boundary between the Paleocene and the Eocene in deep-sea cores is an abrupt shift in oxygen isotope ratios in foraminifera towards a lighter value -The shift signals a temperature change -Even in Antarctica, surface and deep-sea waters became 8 degrees warmer than today's oceans Understanding the pulse of warming: Methane Hydrates: -Metabolic activity of Archaea is one of the primary sources of atmospheric methane. -Methane concentrations in the atmosphere are usually low because nearly all of it becomes oxidized to CO2, within a few tens of years of exposure to atmospheric oxygen -Methane generated by Archaea becomes stored (in the absence of free oxygen) in an icy state called methane hydrate: methane frozen within a cage of water molecules -Masses of methane hydrate constitute the largest fossil fuel reservoir on Earth BUT it is hard to exploit for energy because of its frozen state −They only exist in a combination of low temperature and high pressure in the absence of O2 -On land and at high latitudes, methane occupies the permanently frozen zone below the tundra, extending down to depths of ~2km—these non-marine methane hydrates are too deeply buried to be readily melted **Masses of methane hydrates also occur profusely in marine sediments of continental slopes--these are easily melted by environmental change **So, warming of the seas at depth of the continental shelf can cause large volumes of methane hydrates to melt during brief intervals of geologic time **Result: positive feedback because global warming releases methane, which accentuates greenhouse warming to cause further global warming *CH4 is more than 20 times as effective as CO2 in warming Earth's atmosphere* -A small amount of greenhouse warming from an initial release of methane would have led to further melting of methane hydrates and further warming in early Eocene -Greenhouse warming would have weakened in a few years--as the methane added to Earth's atmosphere oxidized to CO2 -Recall that several physio-chemical and biological reactions discriminate between molecules carrying heavy or light isotopes, with reactions preferentially occurring with molecules carrying the light isotope -Biologically produced methane carries a light C isotope signal that carries through as methane becomes oxidized in the atmosphere -Once converted into CO2, primary producers carry this light C enrichment back to the ecosystem − release of methane hydrates along continental slopes Reorganization of faunas due to pulse of warming -A small amount of greenhouse warming from an initial release of methane would have led to further melting of methane hydrates and further warming in early Eocene BUT greenhouse warming would have weakened in a few years as the methane added to Earth's atmosphere oxidized to CO2--> Habitat changes associated with vegetation changes-->Mammalian Great Migration from Siberia to Alaska (via a land bridge that is flooded today by the Bering Sea) −Primates, odd-toed ungulates, even-toed ungulates, members of the opossum family -*brief climatic event profoundly reorganized mammalian fauns on a global scale* Warmth extended to high latitudes -Northerly regions experienced balmy climates during the Eocene -Isotope ratios in foraminifera show that tropical seas were ~5-8 degrees Celsius warmer than today -Forests (widespread in the Eocene) contributed abundant water vapor, which also acts as a greenhouse gas

Methane Hydrates

-Metabolic activity of Archaea is one of the primary sources of atmospheric methane. -Methane concentrations in the atmosphere are usually low because nearly all of it becomes oxidized to CO2, within a few tens of years of exposure to atmospheric oxygen -Methane generated by Archaea becomes stored (in the absence of free oxygen) in an icy state called methane hydrate: methane frozen within a cage of water molecules -Masses of methane hydrate constitute the largest fossil fuel reservoir on Earth BUT it is hard to exploit for energy because of its frozen state −They only exist in a combination of low temperature and high pressure in the absence of O2 -On land and at high latitudes, methane occupies the permanently frozen zone below the tundra, extending down to depths of ~2km—these non-marine methane hydrates are too deeply buried to be readily melted **Masses of methane hydrates also occur profusely in marine sediments of continental slopes--these are easily melted by environmental change **So, warming of the seas at depth of the continental shelf can cause large volumes of methane hydrates to melt during brief intervals of geologic time **Result: positive feedback because global warming releases methane, which accentuates greenhouse warming to cause further global warming

Devonian invertebrates:

-Millipedes and flightless insects--fed on organic detritus (dead plant material, not living plant tissue, was the nutritional foundation for earlier terrestrial communities) -scorpions, centipedes, spiders--carnivores

Isthmus of Panama between North and South America

-Occurs during Early Pliocene ~3-3.5 million years ago -Less mixing of Atlantic and Pacific waters -High salinity of Atlantic waters sinks in northern hemisphere -High altitudes cool -->Allowed migration across North and South America --Some argue that this isthmus caused the modern ice age -Isthmus makes North Atlantic much saltier than Pacific -Increase in 18O to the east of the isthmus apparently resulted from an increase in the salinity of waters there, with evaporation preferentially removing 16O, the lighter isotope

Precession

-Precession (~20,000 year cycles) -Controls at which point in earth's orbit the Northern Hemisphere will experience summer and winter -A slow motion of Earth's axis that traces out a cone over a period of 26,000 years

Early Jurassic

-Quick recovery -Pangaea continues to split due to the separation and further movement of tectonic plates--> leads to elevation changes -creation of new and more coastlines -new subduction and convergence zones: -Andean Orogeny (Andes Mountains) in the Early Jurassic -Fish diversify, including more sizes and types of behaviors -Further moving toward modern types -Niches open up (with the loss of so many archosaurs)

Carboniferous extinction?

-Rainforest collapses- minor extinction event -Amphibians lose diversity -Reptiles remain relatively unharmed

Temperature of Earth in the Miocene--Holocene

-Relatively warm climates spread to high altitudes -Partway through Pliocene, Northern Hemisphere plunged into modern ice age -Since, climates in many regions have been cooler and drier -Early Pliocene climates were relatively warm -Sea level rose, leaving marine deposits inland of modern coastlines -Fossil faunas and floras show that climates were more equable than today (winters were warmer) -Warm interval came to a close with the start of the modern ice age about 3.2 million years ago

A rift in the American Southwest

-Rifting produced fault-bounded grabens: valleys at the center of a ridge -Today it's somewhat dormant, but not yet declared a failed rift

Volcanism in the Yellowstone region

-Shallow subduction produced volcanism -A large portion of the Yellowstone National Park lies within the Absaroka Range -Volcanism here was episodic, destroyed entire forests -Remnants of the Eocene forests can be seen at high elevations at YNP -Petrified stumps- more than 20 successive forests, all killed by volcanism, have been recognized -Modern volcanic activity at Yellowstone is unrelated to the Absaroka Range- it instead results from the presence of a hot spot

Milankovitch cycles and climate effects

-Source of the glacial oscillations (expansion and contraction) that have characterized the ice age since its inception -Precession (~20,000 year cycles) -Controls at which point in earth's orbit the Northern Hemisphere will experience summer and winter Obliquity (~41,000 year cycles) -Tilt in Earth's axis of rotation -Smaller degree of tilt promotes glaciation -Cooler summers=less melting -More snowfall in winter -Early in the ice age, glacial oscillations corresponded to the obliquity cycle of Earth's axis rotation -At the point in the obliquity cycle when the axis is farthest from vertical, the polar regions are aimed most directly toward the sun during summer and receive maximum sunlight and solar heat -Eccentricity (~100,000 year cycles) -How elliptical Earth's orbit is -Doesn't change the total distance; just the shape -Exaggerates climate difference between farthest point in orbit (aphelion) and closest point (perihelion)

The buildup of atmospheric O2 before the great oxidation event

-There is evidence that until 2.3 billion years ago, chemical sinks were soaking up oxygen so effectively that the concentration of O2 in the atmosphere remained at only 1 or 2% of its modern level -Highly oxidized Fe in all proterozoic soils younger than 1.9 billion years -by this time in South Africa indicates that atmospheric O2 had built up to at least 15% of its present level--this type of oxidation didn't occur early in Earth's history -banded iron formations Michigan (2 Billion years ago) -they are among the oldest known rocks on earth and are quite common in Archean terranes -refers to bedding configuration in which layers of chert alternate with layers of minerals rich in Fe -They ceased to form ~1.9 million years ago because the concentration of O2 built up in the waters of the deep ocean, reflecting a buildup of O2 in the atmosphere

"Sea Monsters" of the Paleogene Oceans

-Unlike whales, sharks descended from similar creatures that lived during the Cretaceous time

Immobile multicellular creatues

-fossils displaying bilateral symmetry in Chinese rocks about 580 million years old -body plan divisible into symmetrical halves on either side of a unique plane -bilateral symmetry entails front and rear anatomical regions, which in modern animals is normally associated with preferential movement in one direction

Phylogenetic tree of the main lineages of Bacteria and Archaea and their proposed divergence times

-genetic data can be useful for estimating when two living organism began to diverge from one another (in the absence of fossil record) -measurements rely on accumulated genetic differences through natural selection -accumulation of genetic changes (or mutation) at a fixed rate provides what is termed a molecular clock -codon redundancy: changes in the third base does not change the amino acid outcome. These are the mutation changes measured in highly conserved proteins (like ribosomes)

Silurian plant invasion:

-invade land by developing rigid stem and root system -living on land does not equal living in water

Snowball Earth

-neoproterozoic glacial deposits occur on all modern continents -this pattern has led some researchers to hypothesize that a "snowball earth" came into being by glaciers on land and by sea ice in the ocean -while the extent of the snowball earth is still debated, Earth has never since experienced glaciation on a scale comparable to that of the Proterozoic (when glaciers spread widely over tropical regions)

Prokaryotic and Eukaryotic fossils of Proterozoic Age

-oldest fossil of a Eukaryote: Algal ribbons -commonly wound into loose coils -date to 2.1 billion years ago -while outnumbered by prokaryotes, single celled algae termed acritarchs become increasingly conspicuous in Proterozoic rocks younger than 2 billion years -dictyoidium with a complex cell wall -gunflint microfossils of Lake Superior (~1.9 billion years old) only include prokaryotic (spheriodal and filamentous) forms

The beginning of animal life

-the composition of the ediacara fauna reveals that animals began to deiversify drmatically about 570 million years ago, slightly less than 30 million years before the end of the proterozoic time. -probably originated during the Neoproterozoic era and greatly diversified to produce a clear fossil record during the last 30 million years of this era ~4 billion years after Earth's origin -three kinds of fossils contribute to our understanding of this expansion: soft bodied fossils, trace fossils, and skeletal fossils *oldest animal like unicellular organisms discovered to date are about 750 million years old. They include skeletons closely resembling the amoeba of the modern world. *evidence from burrowing animals: -sedimentary features that can be unquestionably attributed to animal movement are known only from Neoproterozoic rocks slightly younger than 600 million years. -Laminated siltstone, montana (1.3 billion years old): older proterozoic strata are strikingly well stratified, reflecting the absence or near absence of burrowing animals -Horizontal burrows (worm shaped animals) fossils performed by animals that burrow parallel to the sediment surface and very close to it. A life that entails deeper burrowing into the seafloor requires special adaptation. (too little oxygen deeper in sediment) -Elephant skin (Algal mats): wrinkled pattern reflecting the presence of organic mats formed by thread shaped cyanobacteria or algae that covered many areas of shallow proterozoic seafloor. They would have helped preserve Ediacaran fossils (in addition to the lack of predators at the time.)

The ediacara fauna

-the oldest known undoubted adult animals preserved in the fossil record -its composition suggests that before the end of the Proterozoic eon all three major groups of bilaterally symmetric animals (the lophotrochozoans, ecdysiozoans, and deuterostomes) were likely in existence

Jurassic Period

200 to 145 million years ago Jurassic invertebrates: Further diversification (particularly shelled forms) -Part of Mesozoic Marine Revolution: time when shell-crushing predators diversify, and shelled invertebrates do the same potentially as a way to outcompete their predators -Invertebrate predators exist too such as crabs with claws -Cephalopods (e.g. ammonites and belemnites) are still important components Plant life: -Wetter and warmer than Triassic -Plant life stays similar but becomes more prevalent Jurassic vertebrates: -Marine reptiles continue to diversify and get larger -Pterosauria continue to diversify and get larger -Mammals remain small living "in the shadows" Archosaurs: -The first crocodilians -Dinosaurs: Take advantage of the End-Triassic Extinction -Immediately start to grow faster and larger -More adults -Take advantage of resources Ornithischia: one of two major groups of dinosaurs -Herbivores, start small, bipedal Stegosauria: -Quadrupedal herbivores -Armored, often with plates -Spikes ("thagomizer") Saurischia -Sauropods: -Quadrupedal herbivores -Long necks, Largest terrestrial animals ever -Highest diversity in the Late Jurassic -Morrison Formation (Late Jurassic of western USA)--Deposit from Sundance Sea -Upper size limit of sauropods: 190 ft long Theropods--Bipedal meat eaters *Herbivores need help digesting they may have swallowed gastroliths-stones to help grind up plant material to aid in digestion* Aves--earliest birds that evolved from dinosaurs -Archaeopteryx -The fossils from Solnhofen Limestone (late Jurassic) of Germany show features -Bird features: Contour feathers, asymmetrical, could fly, enlarged area for flight muscles -Reptile/dinosaur features: teeth, long tail, claws on forefeet (hands) End Jurassic Minor Extinction: -Anoxic events in the ocean -Changes in ocean currents since Pangea is still splitting--further warming and climate change -Don't lose any major groups

Permian Period

299 to 251 million years ago Permian reptiles diverge into two major groups. Pelycosaurs: a paraphyletic (common ancestor) group. -Sailed back animals -Temporal fenestra: hole in the back of the skull that relates Pelycosaurs to us Therapsids take over in the late permian. -20 families of Therapsids diversify in 5-10 million years -Endothermic: (warm blooded) high metabolic rate kept their body temperatures higher than their surroundings -legs no longer sprawled like a reptile, more underneath

Diversification in the water

388-444 million years ago (Ordovician, in the Paleoxoic, in the Phanerozoic Eon) -increase swimming forms, burrowers, corals -invertebrates invade fresh water habitats

Obliquity

Axial wobble; tilt of earth's axis changes over time (ranges from 21.8- 24.4 degrees) Obliquity (~41,000 year cycles) -Tilt in Earth's axis of rotation -Smaller degree of tilt promotes glaciation -Cooler summers=less melting -More snowfall in winter -Early in the ice age, glacial oscillations corresponded to the obliquity cycle of Earth's axis rotation -At the point in the obliquity cycle when the axis is farthest from vertical, the polar regions are aimed most directly toward the sun during summer and receive maximum sunlight and solar heat

Lineages present during the Pre-cambrian

Bacteria and Archea, Ancestral Protozoans, Cnidarians, Multicellular ancestors-->Coelomates--> Mollusks, Anthropods, Echinoderms. Modern single-celled algae: Amoebas, Zooflagellate, Ciliates, Dinoflagellates, Diatoms, Coccolithosphores

Ordovician

Cambrian seas: most were floaters, swimmer, and walkers on top of sediment Ordovician seas: lots more taxa burrowing, coral reefs evolve, increase predation -This radiation was the MOST DRAMATIC evolutionary expansion in the marine realm: 3 times the amount of marine families evolved -Nautoloids grew 10 feet and starfish were predators on the floor -Rugose corals: main reef builders in early ordovician -tabulate corals: main reef builders in mid-ordovician

Causes of Mass Extinctions

Causes: -asteroid impacts, environmental changes, volcanic eruptions, release of methane Geologic reasons: Pangea coalesces--Drier and hotter (climate change), Frog species will not do great here Continents and land area connecting have big effects- Also placement globally, Pole- cold; equator- warm. -Easier to create ice on land than in water -Land from one pole to the other- easy to cover it all in ice (snowball earth) -Release of a lot of potentially harmful gases--Form of volcanoes, traps (size of USA) -->Changes in primary production -Plumes block sun plants die off, food chain and other things die off -Release CO2 and methane - cause problems in the air and in the ocean -Volcanic eruptions Astronomically: -Asteroid hitting Yucatan Peninsula- dinosaurs go extinct -Milankovitch Cycles - can affect climate Biologically: -Causing local extinction: North America and South America connected --all the placental mammals went down to South America, hunted all the Marsupials, so all Marsupials went extinct except possums -Different climate can have big effects on certain groups think of PRIMARY PRODUCERS: PLANTS (can create biomass)- hurting them messes up everything -Release of methane

Devonian

Devonian plants -better root system -plants are more terrestrial and get big (Baragwanthia: non marine, large (1m)) -Lycopods (club mosses) evolved -spores and seeds Spores -tiny durable structures adapted for dispersal outside the plant -spore grow into tiny egg and sperm bearing generations -sperm and egg produce adult plant *sperm still require through film of water to the egg, Ferns are still tied to moist environment* Seeds: Durable structures that disperse offsprings -wind carried, animal fur/feces -late Devonian -Seeds allowed plants to move away from moist habitats Devonian invertebrates: -Millipedes and flightless insects--fed on organic detritus (dead plant material, not living plant tissue, was the nutritional foundation for earlier terrestrial communities) -scorpions, centipedes, spiders--carnivores Devonian vertebrates: -jaw evolution--in jawless fish the gills are supported by gill slits (first gill arch=first gill slit) -in jawed fishes first gill arch becomes jaws -first gill arch=upper and lower jaws -jawed fishes diversify -Acanthodians die off at the end of the Devonian--replaced by large fishes -Placoderms--plated skin, dominated fresh water environments -Dunkleosteus:7 meters, size of school bus -other major vertebrate groups evolve: -ray-finned fish (tuna, gar, goldfish)--bones radiate from fins to support fish -lobe-finned fishes: -lung fish, use air to gulp air -Coelacanth -Paired fins attached by a singular shaft -(your ancestor) (Late) Devonian vertebrates -first digited tetrapods (you) evolve -four legged vertebrates related to amphibians invaded land -Pictured: Tiktaalik Roseae--intermediate form between fish and tetrapod -homology: "same relation" biological structure in different taxa appear similar because of shared ancestry

The Cambrian Diversity of Life

Diversity of Energy Metabolisms: Although many animal taxa evolved during Early Cambrian time, they encompassed a narrower range of life habits

Laurentia

During the Proterozoic time, Greenland was attached to North America -1st stage in the formation of Laurentia was the assembly of at least 5 microcontinents into a sizable fraction (between 1.95 and 1.85 billion years ago) -these former microcontinents represent Archean terranes, which lie mostly within the Canadian shield -precambrian rocks also underlie the interior of the continent to the south Archean and Proterozoic Geologic provinces of Laurentia -most Archean terranes were sutured together, but the Superior Province is separated from smaller archean terranes to the west by a broad zone of rocks known as the Trans Hudson Belt -Trans hudson belt comprises deep-sea sediments squeezed up between the converging cratons and crystalline rocks produced by an igneous arc -The largest Archean terrane crops out as far south as Wisconsin. Archean rocks are exposed in uplifted regions of Montana, Colorado, and South Dakota. -slightly before 1.2 Billion years ago, a spreading center formed beneath the late Precambrian craton and began to rift it apart (but ceased before the continent was split)

Early Triassic Period

Early Triassic: What dies out: -Fusilinids -Lacy Bryozoa -Rugose Corals -Trilobites -Eurypterids But what takes advantage of the open spots left by extinction: -Mollusks (bivalves) -Ammonoids -Echinoderms -Stromatolites Recovery of plant life -Gymnosperms ("naked seeds") -Large trees, woody stems -Poor nutrition -Cycads and gingkos -Forests of Pangaea: -Dominated by gymnosperms -Relatively low energy content New dominant reef builder: hexacorals

First major mass extinction

End of Ordovician Extinction -mass cooling causes 70% of life to be lost. 2nd largest extinction on the planet. 20 families go extinct per million years. Factors accounting for it: Glaciers on Gondwana--global drop of sea level causes an unconformity who does not make it -groups of: -brachiopods -trilobites -bryozoans -corals -acritarchs -graptolites -conodonts -nautiloids

2nd mass extinction

End of the Devonian -Glaciation event -spread of forests -depleted greenhouse gases -increased weathering -reduced atmospheric CO2 Who does not make it? -many tropical taxa -reef building organisms -coral strome reef community -terrestrial plants -large armored fishes

Continental glaciation (in the Northern Hemisphere)

Evidence 1) Erratic boulders −Certain large rocks that sit on Earth's surface far from exposures of the bedrock from which they have broken—called erratic boulders—are too large to have been transported by rivers, and it is difficult to imagine that any agent other than continental glaciers might have transported them 2) Glacial sediments and till −Glacial till, a mixture of boulders, pebbles, sand, and mud that has been plowed up, transported, and then deposited by glaciers, is seldom confused with sediments deposited by other mechanisms, especially where it rests at Earth's surface and forms moraines or it is associated with outwash deposits. Glacial moraines form much of Cape Cod. Retreating glaciers commonly left terminal moraines behind them, and as glaciers melted back, they often left shallow basins in which water accumulated behind the moraines. The Great Lakes of North America occupy such basins; they did not exist before the modern ice age 3) Depression of the land −Earth's crust remains depressed in regions that lay beneath large glaciers a few thousand years ago. Hudson Bay, the only epicontinental sea that exists today in N. America, occupies such a depressed region in eastern Canada 4) Glacial scouring −Glaciers smoothed the sides of mountains that they scraped past. Mount Monadnock, in New Hampshire, stood partially above surrounding ice sheets, as some mountains of Antarctica do today. The lower part of Mount Manodnock, which was smoothed by flowing glaciers, stands in sharp contrast to the upper part, which remains rugged. Small glaciers, known as alpine or mountain glaciers, left their marks along valleys within the Rockies and other mountain chains, where they flowed during the modern ice age. Especially spectacular are the U-shaped valleys that glaciers sculpted from valleys that were once shaped like a V 5) Lowering of sea level −One important effect of each major expansion of ice sheets during the modern ice age was a profound lowering of sea level as great quantities of water were locked up on land. During major glacial expansions, most of the surfaces that now form continental shelves stood above sea level. Rivers cut rapidly downward through the soft sediments of continental shelves to form valleys that exist today as submarine canyons. During some glacial episodes, sea level dropped to about 120m (400 feet) below its present position. It has been estimated that the volume of ice was nearly three times as great as it is now during glacial maxima of the Pleistocene Epoch, with the largest sheets 2km in thickness. 6) Migration of species −As sheets have expanded repeatedly and sea level has dropped, the resulting geographic changes have allowed species to migrate to new regions. Regression of seas during glacial episodes turned the Bering Strait into a land corridor, and by this land bridge many mammals, including the 1 st humans, entered the New World. This region was hospitable to terrestrial mammals during height of glaciation. The alternations of glacial maxima and minima have caused climatic belts and their floras and faunas to shift over distances measured in hundreds of km.

Evolutionary experimentation

Evolution during the Cambrian period produced many groups of animals that included few genera and species (indeed some are classified as their own classes or even phyla). -This phenomenon is seen in the early Paleozoic history of the phylum Echinodermata (today this phylum includes a few groups such as starfishes and sea urchins) -a number of bizarre echinoderm classes evolved during the Cambrian and Ordovician. None included many species or genera and most survived a short time: Flexible form (probably burrowed) Stationary Form and Free-swimming forms (with tail-like structures) *evolution of new forms is not planned, but rather caused blindly by nature

The Geologic Time Scale

From large to small: Eon, Era, Period, Epoch from beginning to end: 1) "Precambrian supereon": Hadean Eon, Archean Eon, Proterozoic Eon 2) Phanerozoic Eon Paleozoic Era: Cambrian Ordovician Silurian Devonian Carboniferous Permian Mesozoic Era: Triassic Jurrassic Cretaceous Cenozoic Era: Paleogene (Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Holocene) Neogene

Cretaceous Plants

Gymnosperms: -still present and diverse Angiosperms first appear: -flowering plants -hardwood trees -increase in nutritional value -increases in complexity and form--pollen and leaves shown here - insects-->begin to co-evolve with flowers and flowering plants, often as pollinators

New tectonic style of orogeny

In the Oligocene-- New tectonic style of orogeny -Pattern of subduction: a central segment of the subducted plate beneath North America assumed a low angle -Thus, the subducted plate extended far to the east before becoming deep enough to melt and send magma to the overlying crust -At the same time, a basin in Washington and Oregon received deep-water sediments and layers of pillow lava -Laramide Orogeny- what creates the Rocky Mountain -Late Cretaceous -Kula plate subducted under North American plate

Devonian vertebrates

Jaw evolution -in jawless fish the gills are supported by gill slits (first gill arch=first gill slit) -in jawed fishes first gill arch becomes jaws -first gill arch=upper and lower jaws -jawed fishes diversify -Acanthodians die off at the end of the Devonian--replaced by large fishes -Placoderms--plated skin, dominated fresh water environments -Dunkleosteus:7 meters, size of school bus -other major vertebrate groups evolve: -ray-finned fish (tuna, gar, goldfish)--bones radiate from fins to support fish -lobe-finned fishes: -lung fish, use air to gulp air -Coelacanth -Paired fins attached by a singular shaft -(your ancestor) (Late) Devonian vertebrates -first digited tetrapods (you) evolve -four legged vertebrates related to amphibians invaded land -Pictured: Tiktaalik Roseae--intermediate form between fish and tetrapod -homology: "same relation" biological structure in different taxa appear similar because of shared ancestry

Carboniferous amniotes

Key feature- the Amniotic Egg: provides embryo with a sac filled with nutritious yolk and two other sacks The Amnion contains the embryo and the fluid developed in it The Allantois collects waste Key feature- jaw shape and musculature Advanced musculature allowed reptiles to apply heavy pressure and slice food by new bladelike teeth

Mammals Radiation in the Paleocene and Eocene

Mammals: -radiation in the Paleocene and Eocene -It was probably primarily through predation rather than competition that the dinosaurs had prevented the mammals from undergoing evolutionary expansion during the Mesozoic time Mammals radiation in the Paleocene and Eocene -By the end of the Eocene, mammals had diversified to the extent that most of their modern orders were in existence -Paleocene- primates, the order to which humans belong, evolved -Hind limbs and forelimbs that are ancestral to human hands and feet -Eocene-bats acquired the ability to fly; large whales swam the oceans -Primitive carnivorous mammals: Mesonychids: Ankalagon- wolf-sized Andrewsarchus- largest terrestrial predator of the early Eocene Creodonts: Patriofelis- similar size to modern cougar Hyaenodon- similar size to average large dog Primitive herbivorous mammals: -Odd-toed ungulate (Late Paelocene)- expanded first, before even-toed -Dog-sized −Horses, tapirs, rhinos -Even-toed ungulate (Early Eocene) −15cm/20in long −Cattle, antilopes, sheep, goats, pigs, bison, camels •Earliest members of the elephant order: -Early Eocene: Moerithium--pig sized -Late Eocene: Palaeomastodon--twice as tall as Moerithium -Rodents- having originated in the Paleocene, continued to diversify, but they may have attained their success at the expense of multituberculates (also specialized for seed and nuts) -As rodents expanded in the Eocene, multituberculates declined and became extinct in the Oligocene -Bottom line! Mammalian diversity increased in the Eocene—the number of families doubled to nearly a hundred, approximating that of the world today Birds: Diatrymas: the other terrestrial predators of the Paleocene -Large, flightless birds -Appeared to be the dominant predator of forested ecosystems through the Late Paleocene but disappeared late in the Eocene -Most birds were large during the Early Cenozoic -Monkeys and apelike primates appeared during the Oligocene -Animals, formally classified as apes had been present in the Eocene time, but they were relatively small and were only known from jaw fragments and teeth −Aegyptopithecus- arboreal (tree-climbing) animal that is the size of a cat; teeth resembling those of an ape, but head and tail resembling those of a monkey -Its brain was unusually large for the size of the animal, presumably reflecting a high level of intelligence for the Oligocene world -In the Neogene time, before the appearance of humans, apes attained considerable diversity in Africa and Eurasia

5 Mass extinctions

Mass extinctions are massive, rapid, and widespread drops in biodiversity Causes: -asteroid impacts, environmental changes, volcanic eruptions, release of methane 1) First major mass extinction: End of Ordovician Extinction -mass cooling causes 70% of life to be lost. 2nd largest extinction on the planet. 20 families go extinct per million years. Factors accounting for it: Glaciers on Gondwana--global drop of sea level causes an unconformity 2) End of the Devonian: -Glaciation event -spread of forests -depleted greenhouse gases -increased weathering -reduced atmospheric CO2 3) and largest extinction event in Earth's history: The Permian Extinction -the rate of extinctions (groups dying) to originations (groups evolving) was skewed heavily in extinction -Potential causes: 1) Siberian traps: massive volcano system that was erupting for a million years. Flood basalts are as big as the united states. Releases CO2 and causes global warming. 2) Pangea formation: the continents coming together changed ocean circulation, increased aridity, large vast deserts formed and animals could not quickly adapt. 3)Increased respiration from marine bacteria. Methane release and decrease in phytoplankton activity. Releases co2 and causes global warming . 4) Anoxic water upwelling: oxygen depleted waters spread upwards killing animals in shallow water Who goes extinct: -80% of all species on the planet -Eurypterids, Trilobites, Acanthodians, Tabulate and Rugose corals are 100% extinct -the only mass extinction to effect insects 4) End Triassic Mass extinction: ~201 million years ago 4th mass extinction -Happens quickly -35% of marine genera go extinct -At least 50% of total species went extinct -Conodonts disappear -All non-dinosaur and non-crocodile archosaurs go extinct 5) End-Cretaceous Mass Extinction

Global biogeochemical cycles

Metabolic reactions involved in cycling elements as different chemical species (compounds) and different oxidation states (degree of loss of electrons) -major biogeochemical cycles were stablished during the Archean Eon (including O2 respiration) -respiration and photosynthesis

Eocene-Oligocene Transition

Middle Eocene: cooling issued from plate tectonic movements involving the rifting of Australia and South America from Antartica Early Oligocene: This resulted in the origin of the south polar glacier, which has never melted since that time. Deep-sea waters also cooled at this time. Results in transformation of ecosystems around the world

Plate tectonics and animals in Miocene

Miocene Epoch--which is in the Neogene period and the Cenozoic Era Plate tectonics and animals in Miocene -Plate similar to modern arrangement, but North and South America were not connected -C4 grasses radiate: -Analyses of ancient grassland soils and of teeth of herbivores that grazed on grasslands revealed a pronounced shift toward heavier carbon isotope ratios between 7 and 6 million years ago −Isotope ratio of carbon reflects the ratio in the plants that produced it −Shift reflects partial replacement of the group of grasses known as C3 grasses by C4 -More effective at converting CO2 than previous C3 grasses -When C4 grasses extract CO2 from the atmosphere, they assimilate a larger fraction of carbon 13 than C3 grasses do -Better at using 13C in their structure -Expansion of C4 grasses caused problems for grazing herbivores that lacked tall teeth--malnutrition for those animals whose teeth were worn down by grass death: large extinction in North American mammals—especially herbivores of large body sizes that lacked tall molar teeth; only grazing species whose molars were extremely tall survived -What caused this spread of C4 grasses? -Global climatic change −C3 grasses require a cool, moist growing season to flourish while C4 grasses predominate where the moist season is warm (i.e. tropical savannahs) -Coevolution with grass-grazers: −Mammals--Ungulates and Mice -Snakes -Modern birds -General cooling and drying of envrionment -Apes radiate--early human ancestor breaks off -Horses and rhino families dwindled after Middle Miocene in a continuation of the general decline of the odd-toed ungulates -Even-toed/cloven- hoofed ungulates expanded, especially through evolutionary radiation of deer and Bovidae families (Bovidae: cattle, antelopes, sheeps, goats) -Giraffe and pig family radiated, but number of species has since declined -Elephants experienced great success during Miocene and Pliocene, but later declined -Antelopes, cattle, and horses, evolved many species that were well adapted for long-distance running over open terrain and possessed tall molar teeth that could withstand considerable wear from phytoliths -Apes radiate -evolved in the Old World, diversified during the Miocene but declined in number of species as forests shrank (replaced by grassy woodlands and savannahs) in the late Neogene time -Early human ancestor breaks off -Abundant C4 grasslands -Mammals doing well: -Giant sloths -Big cats and sabretooth tiger -Mastodons and mammoths -Wolves and bears -New predator/prey relationships: -Macrauchenia (goes extinct) -Overhunted by predators from North America Isthmus of Panama between North and South America -Occurs during Early Pliocene ~3-3.5 million years ago -Less mixing of Atlantic and Pacific waters -High salinity of Atlantic waters sinks in northern hemisphere -High altitudes cool -->Allowed migration across North and South America --Some argue that this isthmus caused the modern ice age -Isthmus makes North Atlantic much saltier than Pacific -Increase in 18O to the east of the isthmus apparently resulted from an increase in the salinity of waters there, with evaporation preferentially removing 16O, the lighter isotope

Human evolution

Miocene Epoch= The Age of Apes -Humans as one species of genus -Superfamily Hominoidea includes hylobatidae, Hominidae (humans), and pongidae (gorilla, chimps, orangutans) Early apes radiated in Africa and Asia -Migration from early apes around 15-16 million years ago, moving to Eurasia -For most of the Miocene the Old World (Africa and Eurasia) was much more heavily populated with apes than Africa is today -Hominoids (our lineage) were able to migrate from Africa a little later than 15-16 million years ago -All the lions, elephants, giraffes also migrated (in time when Africa was in contact with other land masses -By the end of the Miocene, there was a small extinction with a loss of many types of mammals (saber tooth tigers, type of sloth) -By the end of the Miocene, a single ape genus survived: Gigantopithecus Miocene-Pliocene boundary: the emergence of early hominids Australopithecus- subfamily within the Hominidae emerging from an unknown group of apes -They're of special interest to humans because we are their only living descendants -Resembled both apes and humans -Ape-like skull with raised brows, smaller skull, human-like flat face, found 6-7 million years ago -Females were 3.5 feet and males 4.5 feet -Resembled both apes and humans (intermediate in form) -Evolutionary increase in brain size and flattening of the face -Sahelanthropus skull fossil found in Chad, Africa (6-7 million yrs old) Lucy (Australopithecus afarensis) -Human-like body, smaller pelvis -Two-legged walking -Upwards-directed shoulder socket allowing them to reach and climb trees -Long, curved fingers- more ape-like; curved bones helped them climb easier -Long, big toes capable of grasping The sudden appearance of the human genus: -Oldest bones associated with Homo genus from 2.4 million years ago -It appears that 2 or more species of Homo were in existence 2 million years -Fossil skulls reveal a large cranial capacity and smaller teeth -"Handy man" stone tools associated with Homo habilis—shown to be smarter animals, creating tools for themselves--Oldowan tools *The origin of early Homo and the extinction of Australopithecus probably resulted from changes that occurred in the climate and vegetation of Africa between 2.6-2.4 million years ago* Homo erectus (2.4 million years old; became extinct ~300,000 years ago) -Smaller pelvis and skull size, walk on 2 feet -More closely related to us -First hominid to migrate beyond Africa (Homo habilis stayed behind) -Peking man- by 1.9 million years it had reached China -Java man- by 1.9 million years it had reached Java Homo heidelbergensis (200,000-700,000 years old) -They manufactured acheulian tools Homo neardenthalensis (50,000-200,000 years old) -The lineage between H. neardenthalensis and H. sapines branched from some common ancestor more than 500,000 years ago -They reached to Central Asia at ~28,000 years -They lived in difficulty from Ice Age in Central Europe -Element of community -They took care of sick/wounded members of their group -Religion--They prepared their dead for a future life Cro-Magnon People and the Late Neolithic Culture (evolved slightly before 150,000 years old) -Larger skulls than modern humans -Built culture, abstract thinking, building things related to the arts and imagination -Human evolution of arts and our ability to manipulate Earth's environment to fit our needs so we don't need to migrate

The emergence of early hominids

Miocene-Pliocene boundary -Humans as one species of genus -Superfamily Hominoidea includes hylobatidae, Hominidae (humans), and pongidae (gorilla, chimps, orangutans) Early apes radiated in Africa and Asia -Migration from early apes around 15-16 million years ago, moving to Eurasia -For most of the Miocene the Old World (Africa and Eurasia) was much more heavily populated with apes than Africa is today -Hominoids (our lineage) were able to migrate from Africa a little later than 15-16 million years ago -All the lions, elephants, giraffes also migrated (in time when Africa was in contact with other land masses -By the end of the Miocene, there was a small extinction with a loss of many types of mammals (saber tooth tigers, type of sloth) -By the end of the Miocene, a single ape genus survived: Gigantopithecus Miocene-Pliocene boundary: the emergence of early hominids Australopithecus- subfamily within the Hominidae emerging from an unknown group of apes -They're of special interest to humans because we are their only living descendants -Resembled both apes and humans -Ape-like skull with raised brows, smaller skull, human-like flat face, found 6-7 million years ago -Females were 3.5 feet and males 4.5 feet -Resembled both apes and humans (intermediate in form) -Evolutionary increase in brain size and flattening of the face -Sahelanthropus skull fossil found in Chad, Africa (6-7 million yrs old) Lucy (Australopithecus afarensis) -Human-like body, smaller pelvis -Two-legged walking -Upwards-directed shoulder socket allowing them to reach and climb trees -Long, curved fingers- more ape-like; curved bones helped them climb easier -Long, big toes capable of grasping

Carbon cycle: negative feedbacks

Negative feedbacks- reduce global warming With increasing temperature.... 1) Chemical weathering increases *Carbonate silicate cycle describes the weathering of continental, silicate rocks in response to increased levels of CO2, which in turn produces carbonate (effectively trapping atmospheric and oceanic carbon in its mineral structure) 2) Primary productivity increases *Increase of the sheer volume of CO2 in the atmosphere and ocean allows photosynthetic organism to radiate. These organisms go on to convert more CO2, releasing oxygen and trapping carbon. *Occurs both on land and in the ocean. In the ocean, Diatoms, coccolithophores, and other phytoplankton while the warmer more humid climate on land promotes terrestrial plant growth. 3) Blackbody radiation increases *Simply and fundamentally, celestial bodies release more heat when they are hotter, accelerating the rate at which they cool. 4) Le Chatelier's Principle- equilibrium opposes forcing *When stressed, equilibrium in a system will shift to oppose the stress: if we increase the amount of reactants in the system, equilibrium will want to increase the consumption of those reactions; if we increase the amount of products, the system will shift to reduce those products.

Plants initial arrival onto land

Origin of plants--first vascular plants--first seed plants--diversification of flowering plants -descendants of green algae make it on to land -mosses and liverworts -still very close to waters' edge

Cretaceous Orogenic events

Orogenic Events -Laramide Orogeny- what creates the Rocky Mountain -Late Cretaceous -Kula plate subducted under North American plate -Alpine Orogeny- what creates the Alps -Cretaceous into Cenozoic -Collision of African and Arabian plates with Eurasian plate (Africa and Middle East with Europe) "India's Run to Freedom": -India separates from Africa -Begins in the Late Cretaceous (~80 million years ago) -Movement started at about 18-20 cm per year (very fast) -Slowed to about 4.5 cm a per year in Paleocene around 55 million years ago (still fast) -Collides with Asia about 10 million years ago

Paleogene Period (in the Cenozoic Era)

Paleogene Period: Paleocene, Eocene, Oligocene Epochs -What remained at the start of the Cenozoic Era were marine taxa that persisted as familiar inhabitants of modern oceans, such as bottom-dwelling mollusks and teleost fish -On land, flowering plants of the Paleogene resembled those of the latest Cretaceous time in many ways -Animal life changed dramatically as dinosaurs were replaced by mammals -marine life recovered "Sea Monsters" of the Paleogene Oceans -Unlike whales, sharks descended from similar creatures that lived during the Cretaceous time The evolution and expansion of the sand dollar: Sand dollar--the only sea urchin able to live along sandy beaches Mammals: -radiation in the Paleocene and Eocene -It was probably primarily through predation rather than competition that the dinosaurs had prevented the mammals from undergoing evolutionary expansion during the Mesozoic time Mammals radiation in the Paleocene and Eocene -By the end of the Eocene, mammals had diversified to the extent that most of their modern orders were in existence -Paleocene- primates, the order to which humans belong, evolved -Hind limbs and forelimbs that are ancestral to human hands and feet -Eocene-bats acquired the ability to fly; large whales swam the oceans -Primitive carnivorous mammals: Mesonychids: Ankalagon- wolf-sized Andrewsarchus- largest terrestrial predator of the early Eocene Creodonts: Patriofelis- similar size to modern cougar Hyaenodon- similar size to average large dog Primitive herbivorous mammals: -Odd-toed ungulate (Late Paelocene)- expanded first, before even-toed -Dog-sized −Horses, tapirs, rhinos -Even-toed ungulate (Early Eocene) −15cm/20in long −Cattle, antilopes, sheep, goats, pigs, bison, camels •Earliest members of the elephant order: -Early Eocene: Moerithium--pig sized -Late Eocene: Palaeomastodon--twice as tall as Moerithium -Rodents- having originated in the Paleocene, continued to diversify, but they may have attained their success at the expense of multituberculates (also specialized for seed and nuts) -As rodents expanded in the Eocene, multituberculates declined and became extinct in the Oligocene -Bottom line! Mammalian diversity increased in the Eocene—the number of families doubled to nearly a hundred, approximating that of the world today Birds: Diatrymas: the other terrestrial predators of the Paleocene -Large, flightless birds -Appeared to be the dominant predator of forested ecosystems through the Late Paleocene but disappeared late in the Eocene -Most birds were large during the Early Cenozoic -Monkeys and apelike primates appeared during the Oligocene -Animals, formally classified as apes had been present in the Eocene time, but they were relatively small and were only known from jaw fragments and teeth −Aegyptopithecus- arboreal (tree-climbing) animal that is the size of a cat; teeth resembling those of an ape, but head and tail resembling those of a monkey -Its brain was unusually large for the size of the animal, presumably reflecting a high level of intelligence for the Oligocene world -In the Neogene time, before the appearance of humans, apes attained considerable diversity in Africa and Eurasia

Order of Paleogene

Paleogene is a period in the Cenozoic Era. Epochs inside of the paleogene are: the Paleocene, then Eocene, Oligocene, Miocene

Modern single-celled algae

Photosynthetic protists -dinoflagellates: they employ two flagella for limited locomotion, but are mainly transported by water movements in which they drift. When conditions are unfavorable to survival, some species enter a state of dormancy through the formation of a cyst. -diatoms: they secrete a two part skeletons of opal, a form of silicon dioxide that differs from quartz in lacking a crystal structure. At certain times in the geologic past, diatoms have flourished to the extent that their skeletons produced thick bodies of sediments. -coccolithophores: They secrete shield-like plates of calcium carbonate that overlay to serve as armor against small attackers. Concentrated accumulations of plates from coccolithophores have been weakly lithified to become chalk.

Silurian-Permian

Plant and Animal land invasion 444-251 million years ago (Silurian, Devonian, Carboniferous, Permian, in the Paleozoic, in the Phanerozoic eon) -increase marine diversity in the Silurian and Devonian -plants invade terrestrial environments -amphibians invade land -reptiles evolve

Deuterostome

Right side of tree of animalia Developmentally the single-celled zygote evolved an anus before a mouth Deuterostomes include invertebrates and vertebrates Echinoderms: seastars, crinoids, sea urchins, graptolies Chordata (us!) -notochord: flexible rodlike structure running the length of the body (our intervertebral discs and vertebrae) -Nerve cord: long stem of the nervous system (our spinal cord) Vertebrata (still us) Carboniferous amphibians: -They were diverse and dominated Carboniferous environments -Range of sizes from 5mm to 7 meters Carboniferous amniotes -Key feature- the Amniotic Egg: provides embryo with a sac filled with nutritious yolk and two other sacks -The Amnion contains the embryo and the fluid developed in it -The Allantois collects waste -Key feature- jaw shape and musculature -Advanced musculature allowed reptiles to apply heavy pressure and slice food by new bladelike teeth

Seeds

Seeds allowed plants to move away from moist habitats Durable structures that disperse offsprings -wind carried, animal fur/feces -late Devonian

Silurian

Silurian diversity recovery -60% of marine invertebrates lost -trilobites do not recover -new niches aren't made: reinvade old niches -brachiopods, bivalves, graphtolites diversify Silurian plant invasion: -invade land by developing rigid stem and root system -living on land does not equal living in water -vascularity--stems have special set of tubes that cary water and nutrient up from the roots to distribute to the rest of the plant--what problem does this solve? what problem does this not resolve? Silurian invertebrates: -reefs rebound from Ordovician extinction -Orthocones give way to ammonoids -complex swimming forms -defensive forms--everything has a shell Silurian Lophotrochozoans: -have either a trochopore larval stage or a feeding structure called a lophophore -mollusks, gastropods, cephalopods, bivalves, monoplacophora -ammonites: coiled cephalopods (rapidly diversified) -Nautiloids did not diversify rapidly Silurian Ecdysozoians -Eurypterids--swimming arthropods, relatives of scorpians, brackish and freshwater forms Silurian vertebrates: -jawless fish -ostracoderms: bony skin, paired eyes, bony armor, hemicyclaspis, pterspis -Acanthodians: paired fins, scaled covered, bodies, more advanced fish

No more dinosaurs...

The Paleogene period= age of mammals (and birds) in Cenozoic Era

3rd Mass Extinction: and largest extinction event in Earth's history

The Permian Extinction -the rate of extinctions (groups dying) to originations (groups evolving) was skewed heavily in extinction -Potential causes: 1) Siberian traps: massive volcano system that was erupting for a million years. Flood basalts are as big as the united states. Releases CO2 and causes global warming. 2) Pangea formation: the continents coming together changed ocean circulation, increased aridity, large vast deserts formed and animals could not quickly adapt. 3)Increased respiration from marine bacteria. Methane release and decrease in phytoplankton activity. Releases co2 and causes global warming . 4) Anoxic water upwelling: oxygen depleted waters spread upwards killing animals in shallow water Who goes extinct: -80% of all species on the planet -Eurypterids, Trilobites, Acanthodians, Tabulate and Rugose corals are 100% extinct -the only mass extinction to effect insects

Later Cambrian Diversification

The earliest vertebrates: -jawless fish -the burgess shale fauna (western of North Africa) -->has yielded fauna of Middle-Cambrian soft-bodied animals that compares with the Early Cambrian Chengjiang fauna -arthropod -polychate worm -onychophoran

Taxonomy

classifying relationships among biological entities -each Domain (Eukarya, Bacteria, Archaea) can be broken down into categories Kingdom Phylum Class Order Family Genus Species -->binomial nomenclature--introduced by Carolus Linnaeus

The Eastern uplift and basins

Today, high up in many areas of the rockies, a person can look into the distance and view a nearly flat surface formed by the tops of mountains

Triassic Vertebrates

Vertebrates Fishes: 1) More modern groups 2) New feed methods (peg-like teeth) 3) Scales more common 4) Better jaws (but still simple compared to today) *Key: distinction between Cartilaginous vs. bony fishes* -Diversity of bony fishes in the Triassic Marine reptiles: -Nothosaurs- some of the first reptiles to enter the water -Plesiosaurs- Evolved from nothosaurs in the Late Triassic, Long necks, full flippers for the water Pliosaurs -Sister to plesiosaurs (Latest Triassic) -But big difference: huge head and short neck Placodonts −Broad-armored bodies −Blunt toothed to crush shells −Potentially turtle ancestors Turtles- first appear in Late Triassic Ichthyosaurs ("fish lizards") −Fusiform (streamlined, torpedo-shaped -Look very similar to modern day dolphins but are very different -Viviparity: live birth—embryos develop inside female rather than outside *Convergence: unrelated animals or plants evolve into similar forms, often due to similar conditions and environments which require similar behaviors* Terrestrial vertebrates -Therapsids (ancestors of mammals) -Endothermy, Upright posture,Live young, Whiskers -Earliest mammals that evolve from therapsids: -Small, nocturnal, potentially arboreal Archosaurmopha (thecodont reptiles- trying out different things) -Includes crocodiles, dinosaurs (and birds) Key features: Teeth in sockets—stronger Holes in skull—reduce weight Bigger muscles on legs and erect gaits Pterosauria: -1st vertebrate fliers (not dinosaurs) -Started small -Possessed teeth, hollow bones, wings Dinosaurs: -Late Triassic -Started small -Bipedal -Legs directly beneath body increased agility and swiftness 2 major groups under the Saurischia division 1) Theropods: meat-eaters 2) Prosauropods: plant-eaters

Is ice a mineral?

YES! • Solid • Inorganic • Naturally occurring • Crystalline structure • Chemical compound

Modern single-celled (animal like) protists

amoebas: ever changing shapes zooflagellates: employ whiplike structure for locomotion (flagellum) cliliates: move by means of numerous cilia-structure that resemble flagella but are shorter and beat in unison.

Phylogeny

reconstructing the history among biological entities -species that form clusters are closely related to one another and have a common ancestry -Rule: each taxon must be traceable to a common ancestor

Vascularity

stems have special set of tubes that cary water and nutrient up from the roots to distribute to the rest of the plant--what problem does this solve? what problem does this not resolve?