* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download The evolution of Life in the History of Earth
Survey
Document related concepts
Geomorphology wikipedia , lookup
Schiehallion experiment wikipedia , lookup
Spherical Earth wikipedia , lookup
Composition of Mars wikipedia , lookup
History of geomagnetism wikipedia , lookup
Provenance (geology) wikipedia , lookup
Tectonic–climatic interaction wikipedia , lookup
History of Earth wikipedia , lookup
Evolutionary history of life wikipedia , lookup
Algoman orogeny wikipedia , lookup
Large igneous province wikipedia , lookup
History of paleontology wikipedia , lookup
Geology of Great Britain wikipedia , lookup
Geochemistry wikipedia , lookup
Paleontology wikipedia , lookup
Clastic rock wikipedia , lookup
Age of the Earth wikipedia , lookup
Transcript
The evolution of Life in the History of Earth Lars Holmer [email protected] Introduction Principles p of Geology gy & Palaeontology Gould: 2222-35 Introduction Palaeontology - the study of the history of life on Earth, stretching over a period of almost 4 billion years y Historical geology - the study of Earth's ‘archive of time’, as represented by the sedimentary record Life on a Changing Earth Life is a continuum - from the earliest organisms to the great variety of species that exist today • Geological events change the course of biological evolution • Conversely, life changes the planet that it inhabits Biosphere - five kingdoms 1. Prokaryotes 2. 3. 4. 5. bacteria Protists Fungi Plants Animals Geologic time When was the Earth formed? When did life on Earth originate? When did life invade the land? What is the rate of biological, chemical, and climatic change? Measuring geologic time Relative dating Absolute dating Absolute dating 1654 James Ussher, Archbishop, Irland - 4004 BC 9.00 (GMT??), 23 October (Sir John Lightfoot) Absolute dating James Hutton (1726(17261797) – The Earth is ancient " ...no vestige of a beginning, no prospect of an end." During the 18th Century absolute dating was impossible Georges-Louis Leclerc Comte de Buffon (17071788) William Thomson, 1st Baron Kelvin (1824-1907) Absolut dating – exact numerical value Radiometic dating • 1896 - Henri Becquerel • 1902 - Ernest Rutherford • radioactive elements decay at constant rates to stable daughter products, e.g. Potassium--Argon. Potassium Relative dating -- the sequence in which the geological events occurred Nicholaus Steno 16381638-1686 Niels Stensen geologist, bishop - & saint! Steno´ Steno ´s laws Law of superposition oldest sediments at the bottom Law of original horizontality - sediments were originally flat lying Law of fossil succession Fossils occur in the same succession over the world – EVOLUION!! Correlation between the sequences Relative Dating: using fossils William ’strata’ Smith (1769--1839) (1769 The father of biostatigraphy The ”map that changed the world” (1815) Geologic time scale Based mainly on the “Law of fossil succession” Eon, Era, Period, Epoch Developed without knowledge of absolute dating Geological time scale All of the names are based on biostratigraphy! Roderick Impey Murchison 1792-1871 Di t G Director Generall Geological Survey of Great Britain 1855-1871 Marloes Sand, Wales Visby The Earth´ Earth´s dynamic system How does it work now? How did it work in the past? Uniformitarianism James Hutton (1726 (1726--1797) Theory of the Earth 1795: ”the past history of our globe must be explained b what by h can b be seen to be happening now”” now The present is the Key to the Past” ” Hutton’s unconformity 100 million years later! 425 million years ago 1. Horizontal deposition of strata 1. Horizontal deposition of strata 2. Tectonic tilting of strata (this takes millions of years) 1. Horizontal deposition of strata 2. Tectonic tilting of strata (this takes millions of years) 3. New horizontal deposition on top Uniformitarianism - gradualism Principles of Geology 1830 1830--33 Charles Lyell (1797(1797•1875) Catastrophism Baron Georges Cuvier 17691769-1832 The history of Life and Earth is mainly shaped by catastrophes WSU, Pullman, A sunny Sunday 18th May 1980, 12:00 500,000 km3 Today, extinctions are a palaeontological fact of life. The K/T event marks the end of the dinosaurs K T The structure of the Earth Oceanic crust - heavier and thinner. Continental crust - lighter and thicker (up to 70 km underneath mountains) 1 = continental crust 2 = oceanic crust 3,4 = upper & lower mantle 5,6 = outer & inner core Distribution of earthquakes along plate boundaries! •Bridge across the Álfagjá rift valley •Eurasian and North American tectonic plates. http://www.ig.utexas.edu/research/projects/plates/teaching_ideas.htm Rifting Rocks & minerals Mineral - A naturally occurring inorganic solid with a crystalline structure and a specific chemical composition Rock - A compact and consolidated mass of mineral matter Three types of rock are recognized: igneous igneous,, sedimentary,, and metamorphic sedimentary metamorphic.. Gneiss, a metamorphic rock Igneous rocks Basalt (volcanic) Gabbro (plutonic) Both of these rocks formed from the same type of magma. But while basalt cooled quickly after a volcanic eruption, gabbro cooled slowly at several kilometers depth The Phanerozoic of Sweden Only 20% C b i -Silurian CambrianCambrian Sil i Mesozoic only in Scania Sedimentary rocks & environments Sediment refers to any loose unconsolidated material, such as sand, clay etc. Sedimentary rock – forms through compaction, cementation) lithification (e.g. compaction, Sedimentary rocks cover approximately 75% of the Earth’s surface (Sweden being an exception) Sedimentary environments include: Terrestrial (deserts, rivers etc) Sedimentary environments include: Shallow marine Sea level Sea rising 8.000 m? The Recent biosphere approx. 13.6 million species •Insects (8,000,000) •Insects •Fungi (1,500,000 ) •Baccteria (1,000,000) •Ba •Spiders •Spi ders (750,000) •Virus (400,000) •Algae •Alg ae (400,000) •Nematodess (400,000) •Nematode •Plants (320,000) •Protists (200,000) •Molluscs (200,000) •Crayfish (150,000) •Vertebrates (50,000) •Other (250,000) Fossils Latin, fossilis - originally anything that was dug up Now - remains or traces of any recognizable organic structure preserved from pre pre-historic times Taphonomy Taphonomy Taphonomy Usually ends with complete destruction Occasionally the process of decay is partially stopped Special preservation - Lagerstätten Uniquely preserved fossils including soft body anatomy Rapid burial, lack of oxygen etc. E.g. Solnhofen (Jurassic), Special preservation - Lagerstätten Amber (fossil (fossil resin; Baltic mostly Oligocene pine tree) Deep freezing (Siberian fauna from the tundra, including mammoths) Special preservation - Lagerstätten Mummification Tar p pits ((open p ‘oil wells’ like those at La Brea, Los Angeles) Peat bogs (the 2000 years old ‘bog people’ from Denmark), Modes of fossilisation Mineralization - cavities in skeleton filled with mineral Replacement - original skeleton dissolved and replaced by another mineral (silicification) Natural moulds - original skeleton dissolved, but not replaced Carbonisation - removal of the ‘light’ constituents leaving coalcoallike film of carbon Trace fossils Hard parts – shells and skeletons Calcium carbonate Calcium phosphate p osp a e Silica Organic Summary Gaia, Historical Geology, Palaeontology Geologic time Geologic time scale Earths structure/dynamic system Rocks, minerals Sedimentary rocks Fossils & taphonomy