In all animals, including humans, successors to free-living bacteria are called mitochondria and are literally our bodies’ power stations.
At one moment in Earth’s history, two bacteria successfully formed a union and the offspring of that first marriage of convenience evolved into ever-more sophisticated lifeforms right up to human beings and beyond.
The relationship, though entirely mutual, is driven by each other’s individual needs to survive, reproduce and spread. Without this relationship, you couldn’t fuel your multi-cellular body and power yourself using the atmosphere’s oxygen.
The genetic material for this single origin bacteria lives on in the bodies of all animals alive on Earth today, including you.
The remarkable thing is, this one lifeform is probably the most successful on our planet as its mitochondrial DNA is always passed on, down the mother’s side only. Genealogy websites use this to determine human family history, to trace how related you are to others. Two very similar patterns from separate individuals, indicate they have a common ancestor. These lifeforms are the only ones that have managed to skip extinction altogether.
