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Lecture 28

BIOL 104 Lecture 28: Lecture 3:31

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Georgetown University
BIOL 104

*Most of this lecture just really went way over my head. The first image of mars was taken in 1960-something and it flew by and took pictures. They discovered craters on Mars. - Craters meant little water, plate tectonics, and hydrolicsystems - Didn’t actually have lines - Didn’t show life on Mars, but people thought there might be! Mars apparently had an atmosphere and environment similar to Earth’s at first but then changed differently. “Organisms with an interest in the conservation of heat and water may select larger sizes” – Carl Sagan life detection experiments - designed to detect metabolism - GSMS found no organics except chloromethane and dicholomethane (cleaning fluids?) - hard to make sense of other results Put there were problems--- - experiments designed to detect metabolism involving organic molecule - all three assumed that we would be able to culture any Martian organisms that were present - we can only culture less than 1% of the organisms on Earth, so we still could have been missing some form of life We found a rock that’s 4.1 billion years old - was on the surface of mars until 14 million years ago - and captured by hearth until 13,000 years ago - fell into Antartica, was covered with ice unti 700 years ago - and recovered in 1984; eventually discovered that it was from mars but was different from other Martian meteorites - There were polycyclic aromatic hydrocarbons (PAHs) which worm as decay products of microorganisms - And magnetite crystals that are similar to crystals produced by some Earth Bacteria - Carbonate globules and ovoid structures - And so long story short it had a nanofossil! - except they could have been produced by nonbioloogical processes and were probably too small to be living
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