positive selection

None of us could live without mitochondria. These are the power centers ubiquitous in eukaryotic cells. They contain molecular machines in factories whose jobs are to generate and conduct electrical currents. The currents run turbines that packetize the energy in molecules of ATP, which are then used by most processes in the cell. New discoveries continue to fascinate scientists with how mitochondria work. Some scientists use their energy to find ways Darwinian evolution could build the machinery of life.