HIST 1003 Chapter : French Revolution 2
Document Summary
11/25/2013 7:31:00 pm: earth is 4. 5 billion years old, early earth was thought to be very hot with a lot of volcanic activity and electrical storms, early earth atmosphere lacked oxygen gas. Life begun during the precambrian era: the oldest fossil organisms found so far are about 3. 5 billion years old, the first cells were presumably anaerobic prokaryotes. Evidence for the endosymbiont hypothesis: there are many distinctive similarities between eukaryotic organelles and living bacteria, mitochondria and chloroplasts each contain their own dna, the presence of living intermediates, ex. Evolution of multicellular organisms: predation provided selective pressure that favored large size, large cells are harder to engulf and digest, larger organisms are usually faster, but there is a limitation on cell size. The ability to exchange materials across the plasma membrane limits cell size: a large cell will have a relatively small surface area through which to obtain nutrients and eliminate waste.
