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SUMMARY:How do we learn about life on Earth billions of years ago? - Profe
 ssor Dianne Newman\, Caltech/HHMI
DTSTART:20111013T171500Z
DTEND:20111013T183000Z
UID:TALK33493@talks.cam.ac.uk
CONTACT:Alexey Morgunov
DESCRIPTION:The Earth was formed ~4.6 billion years ago (Ga)\, and traces 
 of ancient life can be found as far back at 3.8 Ga.  What was life like in
  the remote past?  What metabolisms were used to sustain growth?  When did
  critical metabolisms that changed our planet evolve\, such as oxygenic ph
 otosynthesis (the ability to convert water to molecular oxygen)?  In this 
 lecture\, I will discuss how geobiologists approach these questions\, illu
 strating the challenges we face in making meaningful inferences about the 
 nature of life so long ago.  In particular\, I will discuss my research gr
 oup's efforts to properly interpret the meaning of a specific type of biom
 arker called a "2-methyl-hopane"\, which for many years was thought to mar
 k the rise of oxygenic photosynthesis\, but which we now have evidence to 
 suggest represents an entirely different evolutionary process.
LOCATION:Old Combination Room (OCR)\, Trinity College
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