BIOLOGY 207 Lecture Notes - Lecture 7: Great Oxygenation Event, Mycology, Microorganism
Document Summary
Life on earth is one big extended family & it started with microbes. That shows how life on earth is one big extended family. And it all started from microbes speci cally bacteria. So, the age of the earth radiates out in both directions from the center at 4. 5 billion years ago at about 3. 5 billion years ago. That"s where we have evidence of life verse beginning the last universal common ancestor luca. And so as the world gets out of older as it radiates out. You can see there are more and more bacteria populating the earth at about 2. 5 billion years ago. A bacterium evolved the ability to perform photosynthesis taking carbon dioxide from the atmosphere using light. And in the process, making sugar for the cell to grow. And one of the byproducts of this reaction was the generation of oxygen. So this bacteria that caused the great observation event is an ancestor of cyanobacteria.
