What actually made possible the emergence of complex life in our planet ?
Every complex life form here on our planet, including you and me has relied on the same solution for what seemed like an insurmountable hurdle, getting enough energy.
Around 2 billion years ago, when nothing lived on the earth except microbes. We think one microbe injested one another. Nothing particularly remarkable happened all the time. But this time the microbe was engulfed but not digested. It actually survived in the host and became a part of it. This microbe had a super power. It generated energy using oxygen, allowing it to extract 15 percent more energy from it’s food. This is the moment when life as we know it really began. The microbe that survived let to what we now call mitochondria.
It lived on in its host , together they started a new life form. A big complex cell. That connect with other cells to make big creatures all of them using oxygen to break their own food. Now Mitochondria inhabits every single cell of every complex life form on this planet. That means they literally power everything that holds life. We all carry the same machinery with us in order to thrive and prosper.
It took trillions of bacteria swallowing trillions of bacteria for more than two billion years before that one failed meal.