EARTH 7 Lecture Notes - Lecture 4: Phanerozoic, Organelle, Multicellular Organism
Document Summary
A brief history of life and deep time. Earth rocks/minerals, moon rocks, and meteorites suggest that the earth and solar system formed ~4. 5 billion years ago. Lord kelvin (1824-1907: earth is 20-40 million years old. First good evidence of life ~3. 5 ga: stromatolites. Oxygen started to grow in the atmosphere around 2. 5 ga. Iron dissolved in the ocean reacted with oxygen7 (rust), forming world-wide iron oxide deposits (2. 5-1. 8 ga) All atmospheric oxygen came from photosynthetic bacteria. Came after the availability of atmospheric oxygen. Eukaryotes: everything else we know: more complex, nuclear envelop protects dna, organelles. There was already a complex, ancestral, eukaryotic cell: predator. That cell engulfed an aerobic (able to use oxygen to make energy) bacterium: endosymbiosis. The engulfed cell became useful to the predatory cell, and would later become mitochondria! This also happened with cyanobacteria (photosynthetic bacteria) chloroplasts. Cellular membranes: chloroplasts and mitochondria have inner membrane made by organelle, and outer membrane made by host cell.
