290 likes | 465 Views
History of Life on Earth. Understanding Time and Life. Evidence for the Universe and Space-time. Time we understand…. Age of the bacteria in my throat: ~.0082 years Age of you: ~15 years Age of a Galapagos tortoise: ~170 years Age of a Bristlecone Pine Tree: ~10,000 years. Deep Time.
E N D
Understanding Time and Life Evidence for the Universe and Space-time
Time we understand… • Age of the bacteria in my throat: ~.0082 years • Age of you: ~15 years • Age of a Galapagos tortoise: ~170 years • Age of a Bristlecone Pine Tree: ~10,000 years
Deep Time • Age of the Earth: ~4,540,000,000 years • Evidence: Zircon Crystals • Age of the Universe: ~13,798,000,000 years • Evidence: Microwave Background Radiation
Extant Life on Earth • ~10 million species inhabit Earth today
Fossils show the past events • Fossil: • Preserved remains/traces of an organism from the past • Records of past life and change over time • Age of a fossil: • Radiometric dating determines the age of the rock • http://www.youtube.com/watch?v=ClJ5lwl_wM0
What is a fossil? • Law of Superposition • Earth is made of layers of rock with the bottom layers being the oldest, upper layers being the youngest • What does that tell us about the fossils we find in those rock layers?
History of Life on Earth Precambrian Era
Major Event: Planet Earth Forms • ~4.6 bya: • Planet Earth forms from solar system collisions • Physics, chemistry & geology everywhere • Earth looks much different than today! • No Water • No Oxygen • No Life • No fun
Major Event: Planet Earth Cools • ~4.6 – 3.8 bya: • Rocks cool & oceans form • Evidence: asteroids, comets, meteors, computer models
Major Event: Prokaryotic Organisms • ~3.8 – 3.5bya: • Cyanobacteria exists & produces oxygen • Evidence: Stromatolite fossils (at field museum)
Major Event: Eukaryotic Organisms • ~2.1bya: • Complex cells with organelles exist • Evidence: fossils, endosymbiosis theory
Major Event: Multicellular Life • ~1.5bya: • Multicellular life exists • Evidence: fossils, colonial flagellate hypothesis
History of Life on Earth Cambrian to Present
Major Event: Animals Diversify • ~530mya: • Animals exist during the Cambrian Period • Evidence: burgess shale fossils (see field museum) http://www.youtube.com/watch?v=S_NPj55hcXQ
Major Event: Mass Extinction • ~450 mya: Ordovician Extinction • 90% of all species died • Major glacial event
Major Event: Fish Diversify • ~420 mya: • Fish exist in Earth’s oceans • Evidence: fossils
Major Event: Organisms on Land • ~400mya: • Land plants, fungi, & insects exist • ~375mya: Tiktaalik exists • 1st terrestrial tetrapod • Amphibians & Reptiles exist
Major Event: Mass Extinction • ~250mya: The Great Dying • 96% of all species died • Asteroids & Volcanoes
Major Event: Reptiles Diversify • ~200mya: • Dinosaurs dominate Earth, small mammals exist • ~150mya: • Birds exist
Major Event: Mass Extinction • ~65mya: K/T Extinction • 75% of all species died • Giant asteroid slammed into Mexico
Major Event: Mammals Diversify • ~65mya – 2mya • No more dinosaurs!
Major Event: Humans dominate • ~1,000,000 years ago: Homo sapiens exist • Happily ever after…
Major Event: Mass Extinction • TODAY!!! • Up to 140,000 species go extinct each year • Habitat Destruction, Hunting, Pollution…