Evolution & Extinction Notes Pt. 2 8.10.09 3:04 PM Get EXAMS back next wek. Science is always changing, more data, new theories and generalizations Two kinds of Ages: ? Relative ? Absolute ? Known Dates o civil War 1861-1865 o WWII GEOLOGICAL TIME SCALE ? based on relative time Absolute Ages ? First were based on scripture (Bible) Volcano Mt Etna ? Romans, historicaly active (150 BC): one lava flow 1 mile wide. o 90 flows have been reported in historical records o But there are many many layers below! Tok many times longer than huan civilization ? furthermore al of Mt. Etna sits on top of Tertiary rocks!! Mid 19 th century: ?Deep Time? Measuring time: ? Bath tub example o how quickly is it leaving, how long ago was it completely ful? ? just ned thre things: ? a. initial state?120 liters ? b. rate of change?1 liters/day ? c. today?s state10 liters o time=|a-c|/b= |10 liters-120 liters| / (1 liter/day) ? 20 days ? some one could have come in and drained the tub a bit or filed it back up, also evaporation is another factor skewing our answer, or we could add in the amount evaporated and get a more precise answer. Historical Science ? Actualism: rely on OBSERVED processes not ?ad hoc? explanations ? Principle of PARSIMONY: Absolute Ages Salt in Ocean ? Rivers bring dissolved to ocean ? If we know rate salt is added, and how much salt is in ocean, can find age of oceans. [see slide for image] a) Initial State: at the ?begining? ocean had no salt (Na); b) Rate: rate of input of Na by rivers into ocean today = 156 x 10^6 tons /yr c) Present State: quantity of sodium in oceans today o 1. Mass of oceans: 1,178,270 x 10^12 tons o 2. % sodium (Na) in oceans: 1.08% o = mass of sodium (1 x 2): 12,60 x 10^12 tons. Time betwen salt fre and present day ocean?------- ? apparently he says something is wrong with this estimate ? because they don?t calculate the salt that is being removed from the ocean Darwin?s Estimate ? of erosion on 50ft clifs in height, one inch per year o about 30,00,00 years ? but what about the super tal clifs? Lord Kelvin (1824-1907) this dude loves numbers He knows the earth has internal heat ? his methods involves COLING (loss of heat) o Second law of thermodynamics: heat flows from warmer to a colder body ? bread on shelf at bakery you chose the warmest one because it is the freshest o spent the least amount of time betwen its? initial temperature and it?s present tep. His methods was similar to al others ? second law of thermodynamics: heat flows from warmer to a colder body ? Assumes in its earliest stages earth was copletely molten Know o initial state o rate at which condition changes o present state once again we can get time that has passed by time passed = |a-c| / b consequences of Kelvin?s estimates [see slide] ? where his stimates of age of Earth corect? o NO ? Two assumptions that made his calculations way of: o AL the heat in the earth came at the intial time of earth accretion. (no additional source of heat)?WRONG o The earth?s interior was solid and cooled by conduction and radiation only?WRONG Radioactivity Discovered (1896) by Henri Becquerel (1852-1908) Radioactivity associated with release of energy (1903) Natural source of heat within the earth (not known to Kelvin) Ironicaly, it negates Kelvin?s estimates, but provides THE tool for obtaining absolute ages from rocks. BREAD ? Kelvin o Bread starts out at initial heat---? then loses that heat ? Realy the Earth is not like bread and has internal heating processes. Geothermal Heat Flow: internal heat Solar Heat Flow: but solar heat is 10,00x greater than internal heat Lecture 10 8.10.09 3:04 PM Exam stuf. Last Topic ? Aging the Earth o Much older than 600yrs: Mt Etna o 19th century methods: I initial state ? present state I / rate of change ? salinity, erosion, heat (Kelvin) o Kelvin?s approach 20-10 my old earth o o HALF-LIVES Rate of change ? Candle "Roman candle? vs radiogenic nuclides [graph of candle?s amount of change in time while burning.] Radio activity graph loses 50% each tie 10, 50, 25, 12.5, 6.25? [see cool graph] Present Radiometric Dating Methods Cosmogenic Half-life ? C-14 5700 yrs ? Be-10 2.5 M.Y. Primordial ? K-Ar (K-40) 1.3 B.Y. ? Rb-Sr (Rb-87) 48.8 B.Y. ? U-235 704 M.Y. ? ? ? ? We are able to age the cooling of the rock ? when magma gets super hot the argon al leaves because it?s gas, then it cools becomes crystals/rock and picks up potassium which then turns into argon. The Half-Life is proportionaly constant like a clock. Mobilistic Earth ? Historical Development o Continental drift (CD) o Sea Flor Spreading (SFS) ? Concept of Plate Tectonics (PT) Land ~1Kilomiter above sea level land ~4Kiloiter below sea level Mountain ranges too were found to be conected at one point NA and N. Africa Fossil Continental Distributions Some fossil species appear on continents now separated by thousands of iles of ocean/ how did they get there? ? they were mostly land species that were found on separate continents Matching rock types and ages of rocks ? glaciers flow over sediment moving sediment and leave marks that tel how much ice and where they were headed. CONTINENTL DRIFT: an idea before its time ? Alfred Wegener (180-1930) ? continental drift hypothesis (1915) ? Hypothesized existence of single ?super-continent? Pangaea ? ? Pan = al Gaea = earth Al-Earth Isostasy ? block of wod in water o continental crust is thicker so if floats higher o oceanic crust is thiner so it isn?t as high. Wegener?s ideas rejected. Lecture 1 8.10.09 3:04 PM Tuesday study break But stil have SECTION on Thursday Recap: ? Continental Drift o Lots of evidence for continents having moved o a single "super-continent? Pangaea (?pan-G-uh?) Isostasy (buoyancy) ? explains many of the major features on the earth?s surface o ocean basins vs continents ? Isostasy: rigid blocks of the earth?s surface (continental and oceanic material) ?float? on an underlying layer that behaves somewhat like a fluid, not just an elastic solid. Best way to describe this: ?visco- elastic? Continental Drift ? Rejected until 1960 ? Lack of physical mechanism for moving gigantic pieces of crust across globe o Alfred Wegener ? World War I tech development helped people to accept theory. ? On map there are mountains and trenches Oldest ocean flor is much much younger than the continents: ~20 Mil Yrs ? Age strips on the Sea-Floor ? when magma comes out of ridge it crystalizes and catches the Potassium 40 and then as it decays we can sample it and deterine the age. 10/13/09 6 Elevation of ocean floor and continents Why was it difficult to conceive of continents moving? The earth?s surface has two distinct elevations: continents ocean floor lower density same thickness thicker 2.7 3.0 3.3 thicker same density The Earth?s surface is ?floating? on material that behaves visco-elastically, so the surface can move up and down--ISOSTASY The earth?s surface has two distinct elevations: Continental material ~2.75 gm/cc Oceanic floor material ~ 3 gm/cc Continental crust is thicker ~ 35 km Oceanic floor material is thinner ~ 5-10km ?But how do continents move horizontally? Continents would have to plough through ocean floor, like ships through water, but there appears to be no physical mechanism that could explain this. Geothermal Heat Flow Russia: ? Amt of ocean crust produced at ridges is ~equal to amt. lost in trenches 10/8/09 6 time = 0 time = 50MY time = 100 MY time = 0 time = 500 MY time = 4,000 MY If only initial heat, 100 my to reach present temp. If radioactive heat added, it will takemuch longer to reach temp Initial heat only Initial heat + radioactivity Kelvin assumed that all of the earth?s heat was derived during its original formation (~?time when it was taken out of the oven?), and he found that the earth?s interior was still pretty warm today, so he concluded that it was young -- it formed (?came out of the oven?) only 10-100 my ago. But its interior temperature today is not just due to its original heat, but due to the radioactive heat that continues to be produced inside the earth as radioactive isotopes ?decay?. In fact, the earth formed ~ 4,600 my ago (?when it came out of the oven?) . Fundamental problem with Kelvin?s Estimate of Earth?s Age Kelvin: Not a problem with method or calculations Problem with assumptions! (he had no idea about radioactivity) milli-watts/ m 2 Geothermal Heat Flow Heat flowing through earth?s surface from INSIDE?cooling of earth?s interior ~1/1000 x 100 W light bulb/m 2 Solar Heat Flow ~2 x 100 W light bulb/m 2 Solar heating of earth?s surface is ~ x 10,000 greater than internal heating Old Ocean flor is pushed under, older flod is denser, ? continents are always less dense than ocean flor ? divergence ? mountain building due to heat convergence ? ountain building due to the thickening of the point where they met sliding against each other ? not realy any mountain building Swet pictures of Africa splitting apart Convergent plate boundaries ? Convergent plate boundaries vary depending on the type of crust o Ocean?continent ? \ \ o Ocean?ocean ? \ // o Continent?continent ? // \ mountain building Lecture 12 8.10.09 3:04 PM History of Life on Earth 4.6 bilion years ? Pre- Cambrian breaks down into 3 section o Hadean 4.6 BY o Archean 3.8 BY o Proterozoic 2.2 BY ? Most important ARCHEAN (3.8-2.5 Ga) localities o Isua, Grenland 3.8 o Fig Tre, Swaziland 3.5 o Warawona, Australia 3.2 ? 3.5 ? ARCHEAN (3.8 Ga-2.5 Ga) o First datavle rack ? 3.8 Ga ? define boundary betwen Hadean (no datable rocks) and Archean. o Earth re-melted and reset rock record ? FORMATION OF MON probably o Archean Earth: ? Water ? ? YES ? Life ? ? ----- no clues to life LIFE ? What is it? o (?Life is what dies when you stomp on it? ?Dave Barry) o A self-replicating chemical syste o requires energy source to remain stable (metabolism) o CELS: Chemical Composition (CHNOPS) ? carbon biased ? no carbon? Never living o Tree of Life We don?t realy have any solid scientific theories of how life came to be. ? we do know: ? originated in a single place ? before life only inorganic molecules ? life came out of no life o In Chicago they have taken inorganic molecules put them in precise conditions and have created building blocks for life (amino acids) ? Bacteria ? Archaea ? Eukarytoes ? Darwin never hypothesized where life came from only what happens after life happens. ? He said though, the simple things must come first. ? Prokaryote Cel ? DNA not in nucleus ? no organeles ? exclusively unicelular ? single cel ? asexual reproduction ? cloning ? smal ? only external wal ? Eukarytoes Cel ? multicel organisms. o The Biological ?pump? (pumps light C [ 12 C] into organic matter) o CO 2 + H 2 ) ---sunlight (energy)-? CH 2 O + O 2 (Sugar) Stromatolite Formation ? bacteria grow in shalow water/ ? Sediment (brought in by tide) sticks to sticky surface ? the tide moves out and more bacteria grows o a bacteria and sedient sandwich Swaziland Africa we have actual micro fossils 3.5 Ga (Ga = Bilion) fossils Prokarytes: 1) the most numerous and diverse organisms on earth 2) unicelular and have a cel wal 3) Thrive in al types of habitat 4) Very smal in size (1-5 Ám) FIRST EUKARYOTES in Michigan: 2.1 Ga ? Empire Mine, Ishpeming Michigan o In the 90?s carbonized algal structures 2m wide and 10cm long found in 2.1 Ga old MICHIGAN rocks. Proterozoic: evolution speeds up (swet idea for a story, the great flod but actualy happends ) Lecture 13 8.10.09 3:04 PM Late to class. Archean: ONLY PROKARYOTES Animal: Eukaryotes ? Animals (metazoa) ? multi-celular o Tissues ? diferent cels: muscles, epidermal, nerve, etc o Organs ? structures fulfiling diferent functions o Systems ? repertory system, nerves system, etc. Classification of organisms hierarchical Traditional Linaean We wil study 8 phyla: 1. Sponges 2. Corals/Jelies i. these ?hunt? 3. Lophophorates i. lok like clams, fundimentaly diferent than class dominated seas for 20il 4. Moluscs i. Octopus, snails? 5. Anelids 6. Arthropods i. mosquitoes 7. Echrnoderms 8. Chordates i. frogs Bacterium: Prokaryote Plants: Eukaryotes Darwin?s dilema ? He expeted a long PRECABRIAN history: RIGHT! ? Must have been simpler organisms before: RIGHT! o 300 my worth of prokaryotes and 150 my of eukrayotes ? ?. Why did he think that phyla should appear gradualy? 1. Actualism(oresent as key to the past) i. uniformity of laws: F=ma ii. unifority of process 2. gradualism Prelude ~575mya ?Ediacara Fauna? ? Pound Quartzite, Ediacara Hils, north of Sydney Australia 1946 o Impression of circular organism. Details originaly overloked: a diverse assemblage of fossils o Mawsonites, Spriggina, Dickinsonia ? LARGE: many more than >10cm ? Latest Proterozoic [iage of ocean flor] o Large (several inches) o rather simple (no head, eyes, mouth?) o soft bodies (no hard body parts) ? ?Prelude? or Ediacara (where they were found) Burges Shale ? In Canadian Rockies (Middle Cambrian) One of the most important fossil localities discovered 1909 ? was ocean flor, now has been lifted up o list of diferent organisms found here ? lots and lots of Arthropods (insect like) ? 7 of our 8 are already here on darwin?s prediction the slow trickling of phyla ? solid lines are the actual ? doted lines are his predictions this is caled the Cambrian Explosion ? there was live before but this was where lots of animals came into the scene ? short interval of time (20-40my) during which most (8) of the higher taxa (phyla) of animals appeared ? time of rapid evolution ? an interval of extreme?.som3thing [see slide] What caused explosion? 1. Extrinsic physical factor?glaciations, change in composition of atmosphere/oceans 2. Intrinsic factors?hox genes, developmental ?plasticity? i. al of the 8 have a similar protein producing gene ii. evolution can be very rapid 3. Extrinsic ecological factors??empty barel?, escalation. Empty ecological barel ? the vertical bars lineages, the horizontal bars are steps ? large steps occur more comonly during early history of diversification. ? As time goes by the environment fils, success of large steps decreases. Lecture 14 8.10.09 3:04 PM Diversity vs Disparity ? diversity: how many? ? disparity: how diferent? o Phyla are a good rep. of this 5 Major MAS EXTINCTIONS .. 1! Lecture 13" Recap: Earliest Life on Earth Archean (3.8-2.5 Ga)--PROKARYOTES a)! chemistry, b) stromatolites, c) microfossils Proterozoic (2.5-0.5)--EUKARYOTES Grypania~2 Ga Today?s topics: First animals: Ediacarans~0.575 Ga Cambrian Explosion~0.5 Ga Phanerozoic history of animals http://www.youtube.com/watch?v=o5wJiiitH8g! 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 BYA 2. Stromatolites 3. Prokaryotic microfossils Earth formed 1. First microorganisms?chemistry algae, marine invertebrates insects mammals Hadean ! Archean ! !Proterozoic! Bacterium (prokaryote) Animal (eukaryote) Plant (eukaryote) (Actual size relative to eukaryotes below) Archean : ! ONLY PROKARYOTES! Oldest Known Eukaryote Fossils:! Grypania spiralis ! carbonized algal structures 2 mm wide and 10 cm long! Found in rocks 2.1 Ga in Michigan and! abundantly in rocks 1.4 Ga in China, Montana and Michigan! Modern photosynthesizing algae! 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 BYA 2. Stromatolites 3. Prokaryotic microfossils Earth formed 1. First microorganisms?chemistry algae, marine invertebrates insects mammals Hadean ! Archean ! !Proterozoic! Grypania! Eukaryotes! Algae, protozoa! Plants! (multicellular)! Animals (metazoa)! (multicellular)! Fungi! (multicellular)! Protista (Protoctista)! (primarily unicellular)! (algae, protozoa)! Eubacteria! (unicellular)! Archaeabacteria! (unicellular)! prokaryotes! eukaryotes! Phylum chordata chordates show the folowing caracteristics at some point in their life cycle ? notochord-rod-like, store muscular energy ? dorsal holow nerve cord ? ? 3. Chevron-shaped muscle bundles?myotomes ? [picture of modern fish] ? [picture of Cabrian chordate] Next these guys start getting bone ? eventualy they replace their notocord with Vertebrate o they become VERTEBRATES ? fishes (but the below have limbs) ? amphibians ? reptiles ? birds ? mammals no plants yet, the land above the sea level was largely empty, al the action was in the oceans From Water onto Land fish------?tetrapods ? evolutionary transition in the fossil record ? mosaic evolution ? pre-adaptation o uses trait in new ways Breathing: gils lungs Moving: fins legs water is 100x more dense than air water: 1gm/cc air: 0.01gm/cc average animal 1.1gm/cc ? we are basicaly naturaly buoyant air has 20x more Oxygen than water difusion is 50,00x faster in air that water ? gils wont work in the air o dry out o and it's a much more complex system than neded to get O2 out of the air. A lok at fish today: o mudskipper ? gils out of water o Lungs in fish? ? Australian lung fish: Certain fish in stagnate or dirty water wil come to the surface to breath air. o Salamander ? Gils as an adolescent ? loses gils and uses lungs after metamorphosis ? some times if they?re in a place with a seasonal drought they may kep their gils after metamorphosis o Tiktaalik ? Newly found in northern Canada. ? NECK neded for locomotion above water ? so it doesn?t bounce up and down with every step ? it has it?s shoulders disconected from the skul ? fin like arms Lecture 15 8.10.09 3:04 PM Recap: The vertebrates: Devonian? fishes->tetrapods?major evolutionary transition "Like a fish out of water..?" In the news: Giant crack likely to create new ocean in Ethiopia Life?s Big Hits: [time line graphic] Devonian [graphic] transition from fish to tetrapod same thing happened with dinosaurs and birds Eusthenoteron (fins like the modern coelacanth, Latimeria) Devonian "transitional forms" ? the 1-2-many arangeent ? (here five digit fors are not the standard o any where betwen 5 ? 8 could be found.) ? Book: Your Iner Fish ? by: Shubin Why move onto land? ? Resources: availability of new, easily accessible resources (plants and insects on land by Devonian) ? Escape from aquatic predators: move across land to lay eggs so that other fish do not consume them. ? Environmental stress: life in shalow pools which could occasionaly dry up; those ?fish? able to handle drought survive. Origin of tetrapods: mode of life ? clearly stil semi-aquatic ? swiming tail ? early lungs Amniotic egg ? Fewer laid ? more energy involved Larval stage takes place within the egg ? Hatchling ~ "adult" ? Fertilized How do fish move ? by twisting the trunk, tail goes side to side Salamander move in the same movement. modern reptile: the trunk is doing most of the muscular movement, and just using the legs and elevators. Carier's constraint: STAMINA modern day sprowlers can not hold breath. Because the lungs when runing are squished, so they can?t go very far, with one breath. Locomotion in more advanced tetrapods moveent is not side to side but, with the spin, back to front. ? This actualy helps the lungs breath rather than hinder them. DINOSAUUUUUUUUUURS! the leg bone?s bal head turned 90 o so the reptiles could have more advanced forward to back movement. some time in the Triassic they showed up Skeletal morphology (femur shape), indicates that dinosaur had upright postures. This suggests that they had overcome Carier?s Constraint. But how fast were they? ? May lok like they were fast, but is there an INDEPENDENT way of calculating their speed? ? YES from fot prints. size of fot stride length fot length is approximately 1/3 the size of leg length. to get speed, you just ned stride length and leg length, and leg length can be found from the size of the fot. Dino locomotion ? Fotprint data: dinosaurs were capable of high speeds (smal ones- human sprint) ? Upright posture ? next time Physiology: warm or cold bloded? (warm: mamals + birds) (cold: fish + amphibians + reptiles) ? how do we k Lecture 16 8.10.09 3:04 PM RECAP: The Age of Reptiles (Dinosaurs)??reconstructing biology of extinct groups? Life?s Big Hits [see slide] 4 major types ? air ? land ? water ? water ARE DINOSAURS COLD OR WARM BLOD? COLD BLOOD ? Less energy ? Dependant on environment ? leave their young ? no social groups WARM BLOODED ? More energy ? Not dependant on environment temperature ? take care of young ? Herding GROUPS Tracks are found with multiple dinosaurs prints. warm-bloded organisms spaned from pole to pole while cold bloded organisms didn?t span al the way to either of the poles. ? although the temperature gradient was much less extreme not as cold not as hot. Seasonal changed were not very extree Cold bloded : turtles experiment ? skin is same temperature as the environment regardless of size. ? but size has an iportant efect on the rate of cooling o the bigger the body the longer it takes ? the bigger the rom the longer it takes to heat up. Same when cooling BUT! o Clearly size maters o but just exactly what aspects of size ? the ratio of volume and surface area. DINO at least 10x the size of elephant ? [see the graph with s,m,l lizard] so basicaly since large dinosaurs were so big they didn?t have to, or couldn?t, change their at high rate because they were so huge. But they were cold bloded. BIRDS ? air ? water ? land Ryan Thurmer Microsoft Word - Document1
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