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Remember:. Scientific Method 1. Observation 2. Hypothesis 3. Experiment & Collect Data 4. Conclusion Cell Theory 1. living things are made of cells 2. cells are basic unit of structure & function 3. All cells arise from existing cells.
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Remember: Scientific Method 1. Observation 2. Hypothesis 3. Experiment & Collect Data 4. Conclusion Cell Theory 1. living things are made of cells 2. cells are basic unit of structure & function 3. All cells arise from existing cells.
Theories on Early Earth& Life’s Origin What is a theory? - an explanation that is supported by evidence
Describe the Earth as theorized to have formed 4.6 Billion years ago (BYA) - very hot - N, CO2, H2O, methane, NO oxygen 4.4 BYA - theorized to have cooled - water vapor condenses http://www.cosmographica.com/gallery/portfolio2007/content/bin/images/large/340_CometFlood.jpg http://www.space-art.co.uk/images/artwork/formations/Early-Earth.jpg
Can scientists be sure that Earth formed this way? No – physical process of Earth constantly destroys and reforms rock What evidence is there to support this theory? Fossils – hardened remains of plants or animals found in the earth’s crust http://dangerdulcimer.com/fossil.jpg http://images.google.com/imgres?imgurl=http://www.breckminerals.com/images/fossil4.jpg&imgrefurl=http://www.breckminerals.com/fossils.html&usg=__mCXSfPozWApYJiIvTFTcxB0flI8=&h=800&w=690&sz=322&hl=en&start=8&um=1&tbnid=OWxglI-OVfuCjM:&tbnh=143&tbnw=123&prev=/images%3Fq%3Dfossil%26um%3D1%26hl%3Den
Fossils – hardened remains of plants or animals found in the earth’s crust Dating Fossils 1. Relative Dating – older fossils on the lower levels, younger on top 2. Absolute Dating or radiometric dating – measuring active chemicals in rocks http://images.google.com/imgres?imgurl=http://evolution.berkeley.edu/evosite/lines/images/strat_column.gif&imgrefurl=http://evolution.berkeley.edu/evosite/lines/IIIAchronology.shtml&usg=__W60aIrR5yb93lThSoGijETSBwDo=&h=312&w=246&sz=9&hl=en&start=5&um=1&tbnid=hjewpuNCKPH8IM:&tbnh=117&tbnw=92&prev=/images%3Fq%3Drelative%2Bdating%26um%3D1%26hl%3Den
Radiometric Dating • Using isotope half-life • Ex. Potassium-40 • Potassium’s half life is 1.3billion • Ex. Carbon-14 for dating < 50,000 years old • Carbon’s half life is 5730years http://www.google.com/imgres?imgurl=http://facstaff.gpc.edu/~pgore/myart/radgraph.gif&imgrefurl=http://facstaff.gpc.edu/~pgore/geology/geo102/radio.htm&usg=__y8NYQsrpFh7trBQATHlfTHgFjT8=&h=374&w=534&sz=46&hl=en&start=12&sig2=PLxiYB9e8Te2ndiI9V0yWA&zoom=1&um=1&itbs=1&tbnid=eR68i1A29vtiWM:&tbnh=92&tbnw=132&prev=/images%3Fq%3Dradioactive%2Bdating%26um%3D1%26hl%3Den%26tbs%3Disch:1&ei=aKXaTIGPDIP98AbNo6WRCQ
Describe a theory of how life first began on Earth. spontaneous generation – life came from nowhere also called abiogenesis Two people who discredited spontaneous generation. 1. Francesco Redi in 1600s with the meat experiment http://micro.digitalproteus.com/pics/spontaneousgeneration.jpg
2. Louis Pasteur in the 1800s with the sterile broth experiment http://vilenski.org/science/notebook/unit1/historyoflife/pastuer_image.jpg From this point (Pasteur’s experiment) on Biogenesis, the idea that life comes from life, stands accepted.
What are some other theories on how the 1st life formed? 1. Oparin’s Hypothesis - energy from the sun triggered chemical reactions of the gases in the air - producing organic molecules - these molecules fell into the ocean - called primordial soup model http://i8.photobucket.com/albums/a48/frogfishII/Miller.gif
2. Oparins Hypothesis Tested by Miller & Urey - Created organic molecules - Problems with this experiment - lighting not in early earth - hot & cold not at the same time
Current ideas on origin of first life: Organic chemicals information molecules complex molecules formation of protocell (p.383) Process
Review: 2 types of cells Prokaryote (“simple”) Eukaryote (“complex,” because have ________ like m_____ & ch_____)
Theories on the Development of Complex Organisms (getting from a single celled organisim to multicellular) -Estimated first organism using fossils - cyanobacteria (cyano = blue green) (bacteria = prokaryotic) - see board Cyanobacteria O2 ozone organisms that photosyn O2 trapped lightning created breath oxygen
Eukaryotes believed to come later than Pro and by the process of endosymbiosis Endosymbiosis - pre-eukaryotic (prokaryote) bacteria engulfed another (endocytosis), p.385
http://images.google.com/imgres?imgurl=http://evolution.berkeley.edu/evolibrary/images/endosymbiosis/endosymbiosis.gif&imgrefurl=http://evolution.berkeley.edu/evolibrary/article/_0/endosymbiosis_03&h=298&w=488&sz=18&hl=en&start=1&um=1&usg=__1u6GapLe7o7YHSg8o7k9Ot_DApI=&tbnid=gDsS60Pl0OEA1M:&tbnh=79&tbnw=130&prev=/images%3Fq%3Dendosymbiosis%26um%3D1%26hl%3Den%26sa%3DNhttp://images.google.com/imgres?imgurl=http://evolution.berkeley.edu/evolibrary/images/endosymbiosis/endosymbiosis.gif&imgrefurl=http://evolution.berkeley.edu/evolibrary/article/_0/endosymbiosis_03&h=298&w=488&sz=18&hl=en&start=1&um=1&usg=__1u6GapLe7o7YHSg8o7k9Ot_DApI=&tbnid=gDsS60Pl0OEA1M:&tbnh=79&tbnw=130&prev=/images%3Fq%3Dendosymbiosis%26um%3D1%26hl%3Den%26sa%3DN
Estimated Timeline of Earth and Organisms - timeline - chart - Pangea picture
http://www.cyburbia.org/gallery/data/6457/pangea-continental-drift.gifhttp://www.cyburbia.org/gallery/data/6457/pangea-continental-drift.gif
Two types of bacteria (prokaryotes): 1. eubacteria – have peptidoglycan in its cell walls and a cell membrane, bacteria that we “know” 2. archaebacteria – no peptidoglycan, first bacteria, live in extreme environments
Theories of Life on Early Land Cyanobacteria oxygen ozone livable earth Helpful Terminology: mutualism – mycorrhizae – fungus and plant continental drift – (Pangea p.379), movement off, relates to theories of evolution
6 Kingdoms Eubacteria Archaebacteria Protists Fungi Plants Animals http://teachers.westport.k12.ct.us/resource/images/Five_king.jpg