09_BioG101 - C e ll E v o lu t io n Lecture 09 Esther...

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1 Cell Evolution Lecture 09 Esther Angert Beggiatoa with intracellular sulfur Evolution of Cellular Life 1. Numbers and Diversity of Bacteria and Archaea (Prokaryotes) 2. A unifying phylogeny: the Three Domains 3. What everyone needs to know about these microbes (description of some key phyla) 4. The Origin of the Eukaryotic Cell and Endosymbiotic Theory 5. Multicellularity Arose Many Times… Prokaryotic Diversity and Numbers • Numbers: – Estimated 10 30 prokaryotes on Earth – As many as 10 14 microbial cells associated with an adult human body! That’s three orders of magnitude more than the number of people who ever lived (100,000,000,000)! – Our microbes extend our metabolic capabilities and aid in the development of our immune system – Most microbes are benign, or even useful, but we know the most about those that cause us harm (pathogens - disease causing) • Bacteria and Archaea are metabolically versatile… – Aerobic and anaerobic growth – Responsible for carbon cycling ( fix CO 2 , decompose) – Generate components of our atmosphere (O 2 , ozone) – Use light for energy, derive energy from mineral transformations, biogeochemical cycling, fix carbon (CO 2 ), fix N 2 – Breakdown complex organics - bioremediation (using organisms to breakdown or clean-up pollution)! – Some have the capacity to live in environments where we could not survive: “extremophiles” Prokaryotes: Limited Morphological Diversity • Common shapes: cocci (spherical), bacilli (rod-shaped), spirilla (spiral-shaped) • Other shapes: squares, stars, filaments
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2 To grow and reproduce, all living organisms require… A. Oxygen B. Light C. Ambient temperatures ~37°C D. Liquid water E. Nitrogen in the form of N
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This note was uploaded on 10/13/2009 for the course BIO G 1101 at Cornell University (Engineering School).

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09_BioG101 - C e ll E v o lu t io n Lecture 09 Esther...

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