SCMA 1290 Lecture Notes - Lecture 9: Synthetic Biology, Oort Cloud, Photosynthesis
Document Summary
The origin and evolution of life on earth. First evidence for life: ancient stromatolites (rock bed) Stromatolites provide evidence of life 3. 5 billion years ago, making photosynthesis at least this old. In the sea, the early atmosphere didn"t have the oxygen filled atmosphere, back then we didn"t have an ozone layer and uv was able to hit the earth, causing every life to be killed. In the water, uv wasn"t able to actually reach this. Therefore life was first formed at the bottom of the ocean. Three types of rocks; sedimentary, metamorphic, igneous. Sedimentary rocks have the process/layers of stromatolites. Photosynthesis is a complex metabolic process, likely taking a long time to evolve, implying life is much older than 3. 5 billion years. We search for microfossils, or fossilized cells; challenging to find due to rarity of old rocks. Isotopic evidence; 12c to 13c ratio reveals the age of life. Organisms do not process 13 c efficiently.
