Origin of Life - Marine Biology - Lecture Slides, Slides of Biology

Download Origin of Life - Marine Biology - Lecture Slides and more Slides Biology in PDF only on Docsity! yAAlrdEIe Sisicgy Origin of Life When space turned around, the earth heated When space turned over, the sky reversed When the sun appeared standing in shadows To cause light to make bright the moon, When the Pleiades are small eyes in the night, From the source in the slime was the earth formed From the source in the dark was darkness formed From the source in the night was night formed From the depths of the darkness, darkness so deep Darkness of day, darkness of night Of night alone aa Did night give birth Born was Kumulipo in the night, a male Born was Po'ele in the night, a female Born the coral polyp 8 Born of him a coral colony emerged.... aa )) pp. 3-4, Johnson, R.K., 1981. The Kumulipo: Hawaiian hymm of creation. Vol. 1. Topgallant Publishing Co., Ltd., Honolulu, Hawai’ • Suns energy stripped away 1st atmosphere • 2nd atmosphere formed from volcanic outgassing • Primitive atmosphere: CO2, water vapor, lesser amts of CO, N2, H2, HCl, and traces of NH3 and CH4 (3.5 bya) Docsity.com • O2 came in 3.2-2 bya • Autotrophic Organisms: photosynthesis • Another environmental change • Result in evolution Docsity.com Earth’s Atmosphere Docsity.com Evolution of Ozone • Accumulation of free O2 in the atm also led to the accumulation of ozone – Ozone important for blocking incoming UV radiation • Even small amounts of atm O2 leads to enough ozone to provide some protection against UV – Partial screen likely to have formed ~ 1.9 bybp – Presence of this UV filter allowed life to move out of the oceans and onto land – Consistent with the timing of evolution of eukaryotes and higher plants Docsity.com UV Protection by the Ozone Layer Docsity.com • 0.5 billion years ago • Atmosphere O2 to 1% current • Compare to present: 78% N2, 21% O2, 0.04% CO2, + trace gasses • Relatively small, most single cell • Start of multicellularity • Increase in cell complexity Docsity.com Life began~ 3.5 bya Organic molecules (C H O N P S) swimming in shallow seas Stage 1: Abiotic synthesis of organic molecules such as proteins, amino acids and nucleotides Docsity.com Stage 2: joining of small molecules (monomers) into large molecules Docsity.com Stage 3: origin of self-replicating molecules that eventually made inheritance possible Docsity.com Miller and Urey’s Experiment ELECTRICITY!!! Organic molecules like amino acids Docsity.com Produced: • 20 amino acids • Several sugars • Lipids • Purine and pyrimidine bases (found in DNA, RNA & ATP) Docsity.com RNA world • The first genetic material was probably self- replicating, catalytic RNA not DNA; • In “RNA world”, RNA could have provided the template on which DNA was assembled • Once DNA appeared “RNA world” gave way to “DNA world” • The first organisms were not photosynthetic; they were probably heterotrophic Docsity.com Oxygen Earliest Evidences: oldest fossils Oldest photosynthetic microbes 3.5-3.2 B.Y. - Bacterium-like - Unicellular - Evidence for breakdown products of photosynthesis Cyanobacteria, 3.5 B.Y. Stomatolites, 3.5- 0.7 B.Y. Docsity.com Three-domain system Extremophiles Prokaryotes Eukaryotes Look at how this evolution happened! Docsity.com Docsity.com Early prokaryotes may have arisen near hydrothermal vents Hydrothermal vents are rich in sulphur and iron-containing compounds needed for ATP synthesis. Temperatures can reach 120 C. Docsity.com Hot springs in Yellowstone National Park – pigmented bacterial mats Docsity.com 1st dinosaur end of dinosaurs 1st reptiles 1st amphibians 1st land plants 1st fish 1st invertebrates Millions of Years Geologic Time Scale Docsity.com Late Late Permian- Late Cretaceous- etary Se EES EE Wane | | 100 a 3 = 35 Co] ere ss 2 30 2 ° a 2 = 2 — 60 & or 2 = 25 9 $ E 2 4 £ = 20 # 15 I I T | I Be 0 500 400 300 200 100 0 Docsity.com Time (mya) Life during Ordovician 488-443 mya Graptolites, trilobites, conodonts, algae, fish, coral, crinoids, gastropods All known metazoan life confined to the seas and oceans Docsity.com The Ordovician Extinction Event • 450 Ma - 440 Ma, two bursts of extinction occurred, separated by one million years • > 60% of marine invertebrates died; • Gondwana moves south • Sea level falls • Atmospheric CO2 drops • Global cooling Docsity.com The Devonian Period • 416-359 mya • Pangeae forms • Extensive reef building • Age of Fishes • Plants & insects colonize land • First vertebrates colonize land Docsity.com The Devonian Extinction Event • Possibly two to as many as seven related bursts of extinction centered on 365 Ma to 440 Ma, over as little as one half to as many as 25 million years • Marine life most affected • Jawed vertebrates unaffected by the loss of reefs, while agnathans in decline. Docsity.com The Devonian Extinction Event • Leading theories include changes in sea level and ocean anoxia, possibly triggered by global cooling or oceanic volcanism • The widespread oceanic anoxia prohibited decay and allowed the preservation of sedimented organic matter as petroleum Docsity.com The Permian Period • The Earth's most severe mass extinction event, – 96% of all marine species – 70% of terrestrial vertebrate species – mass extinction of insects – Some 57% of all families and 83% of all genera were killed • recovery of life on Earth took significantly longer than other extinction events Docsity.com The Permian Extinction Event • There were from one to three distinct pulses of extinction that occurred about 245-251 million years ago • Several proposed mechanisms for the extinctions: – earlier phase - gradual environmental change – latter phase - catastrophic event Docsity.com The Permian Extinction Event • Suggested mechanisms for the latter extinction pulse include: – large or multiple bolide (meteor/comet) impact events – increased volcanism and sudden release of methane clathrate from the sea floor – gradual changes include sea-level change, anoxia, increasing aridity, and a shift in ocean circulation driven by climate change – Excess CO2 acidified oceans, contributing to the decline of shelled organisms Docsity.com The Triassic Extinction Event • The extinction occurred around 208 million years ago and happened in less than 10,000 years just before Pangaea started to break apart • This extinctions struck marine life and terrestrial life profoundly • At least 50% of the species now known to have been living at that time went extinct • In the seas, a whole class (conodonts) and 20% of all marine families disappeared – Conodonts were early eel-like chordates Docsity.com The Triassic Extinction Event • On land, all large crurotarsans (non-dinosaurian archosaurs) other than crocodilians, some remaining therapsids, and many of the large amphibians were wiped out • This event vacated terrestrial ecological niches, allowing the dinosaurs to assume the dominant roles in the Jurassic period Docsity.com The Triassic Extinction Event • Several explanations for this event have been suggested, but all have unanswered challenges: –Gradual climate change or sea- level fluctuations –Asteroid impact –Massive volcanic eruptions Docsity.com Late Cretaceous Extinction Event • The event marks the end of the Mesozoic Era and the beginning of the Cenozoic Era • Essentially all non-avian dinosaurs, mosasaurs, plesiosaurs, pterosaurs and many species of plants and invertebrates became extinct • Once dinos gone, mammals dominate in next period Docsity.com The Late Cretaceous Extinction Event • The Chicxulub impact, a 10km diameter meteorite, leaving a crater ~200 Km in diameter Impact caused acid rain, ash that blocked out the sun for months, severe global cooling (nuclear winter). Increase in atmospheric CO2, resulting in global warming, final blow to dinosaurs & many other Cretaceous species. Docsity.com The Late Cretaceous Extinction Event • Other possibility: increased volcanic activity (India’s Deccan Traps) The Deccan basalt traps of India were then antipodal to the Chicxulub impact Docsity.com Late Cretaceous K/T Boundary 66 Ma a Od Les OCEAN ees ok eae OCEANS “6 Pi y ae anes = — gs ee ed . ewe ee Subduction Zone [triangles point in the ra cf Se mere Pee) | ra s De —_ oo % NU Camel 6th Major Extinction Golden toad 1989 Yangtze River dolphin 2006 Stellar’s sea cow 1768 Tasmanian Tiger 1936 Quagga 1883 Passenger Pigeon Martha 1914 Docsity.com Hawaiian Honey Creepers Kauai O'O (extinct); Kauai Akialoa (extinct); Kauai O'u (extinct) ; Kauai Nukupu'u (extinct); Puaioho (less than 200 left); Kamao (extinct) Docsity.com