When would you guess, was the first time the sun was used a source to make energy for living organisms?
1 Answer
Around 3.8 billion years ago.
Explanation:
Current thinking is that anoxgenic simple prokaryotic bacteria evolved around this time and shortly thereafter developed a symbiotic relationship with chloroplast bacteria who had evolved the ability to absorb sunlight for energy. Together, they formed a partnership and started to use the sun as an energy source.
Around 2.5 billion years ago, another photosynthesizing cyanobacteria evolved that was able to do this same trick and also released oxygen into the water and then later into the atmosphere as a waste by-product. These cyanobacteria, often called stromatolites, could also survive in an oxygen rich environment.
Pumping oxygen into the water and then the atmosphere fundamentally changed the course of biological evolution on Earth after this time. Around 1 billion years ago, eukaryotic cells (those with a DNA nucleus) evolved and the around shortly thereafter, multicellular eukaryotic cells evolved who could utilize O2 for respiration and metabolism.
