2. Origin of Life

4. Origin of the Solar System Earth is estimated to be ~4.6byo –Radiometric dating of rocks & meteors Nebula: cloud of gas & dust in space Nebula Hypothesis: –Gravity pulled much material to center (Sun formed) –Planets: remaining materials

5. Ancient Earth Atmosphere contents: –Ammonia, H 2 O vapor, Methane, CO 2 Climate: –Extreme heat due to meteor impacts & volcanic activity Eventually Cooling: Water vapor condensed (oceans formed) Click on picture to play video clip

6. Hypothesis: Energy from lightning created organic materials from inorganic ingredients Experimental Set-Up: –Ammonia, H 2 O vapor, Methane, CO 2 gases added –Electricity added (simulate lightning) Result: Amino Acids & later nucleotides Importance: Could this be how life began to take shape?

7. Murchison Meteorite

8. Cell Formation? Iron-Sulfide bubble hypothesis –Hydrothermal vents trapped organic molecules –Wall acted as first cell membrane Liposomes –Spheres of lipids –Can form around organic molecules –Hypothesis: 1 st cell membranes?