4 - PROKARYOTIC DIVERSITY BIOL 4125 SPRING 2009 LECTURE 4...

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Unformatted text preview: PROKARYOTIC DIVERSITY BIOL 4125 SPRING 2009 LECTURE 4 Microbial evolution http://ircamera.as.arizona.edu/NatSci102/lectures/lifeform.htm http://www.psi.edu/projects/moon/moon.html Late heavy bombardment 3.8-4.0 Ga 3.5 Ga Impact of a Mars-sized object with the Earth ~4.5 Ga Pace, N.R. 1997, Science, 276:734-740. Bacteria Eucarya Archaea When the tree of life was assembled using small subunit rRNA gene sequences, it revealed that thermophilic bacteria and archaea are the closest living relatives to the universal ancestor. Was the first life form a Was the first life form a thermophile thermophile ? ? The First Billion Years The First Billion Years O r i g i n o f t h e E a r t h- M o o n 4 . 6 x 1 9 y e a r s M i c r o f o s s i l s 3 . 5 x 1 9 y e a r s C a r b o n a t e I s o t o p e s 3 . 8 x 1 9 y e a r s C r u s t A c c r e t i o n 4 . x 1 9 y e a r s 500 million year window for the Origin of Life HOT!!! O l d e s t r o c k s- m e t e o r 4 . 5 x 1 9 y e a r s B a n d e d I r o n F o r m a t i o n s 3 . 7 x 1 9 y e a r s From From Progenote Progenote to Community in to Community in <500 million years? <500 million years? Microbial mats X-section showing the complex layers in a microbial mat community Upper layers cyanobacteria and other photoautotrophic lifestyles Lower layers sophisticated ecosystem fueled by excesses of reduced carbon from photosynthesis. Fossilized stromatolites Living Microbial Stones Stromatolite building in progress; Shark Bay, Australia NOTE: cyanobacterial morphologies are quite complex and can be used for taxonomic identification...
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This note was uploaded on 08/04/2009 for the course BIOL 4125 taught by Professor Christner during the Spring '08 term at LSU.

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4 - PROKARYOTIC DIVERSITY BIOL 4125 SPRING 2009 LECTURE 4...

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