The image of our cells as some DNA surrounded by cytoplasm is not true. About a billion years ago, life consisted of single-celled organisms afloat in a planet-wide sea. These single cells could not do much because they had no good way to make energy. Then bacteria invaded the ancient ancestors of plants and animals and took up permanent residence. One bacterium eventually became the mitochondria that today power all plant and animal cells; another became the chloroplast that turns sunlight into energy in green plants.
Now scientists have found that a cyanobacterium — which had already developed photosynthesis — invaded eukaryotes 900 million years ago, much later than some estimates, which are as high as 2 billion years ago.
Read more here … or look it up in your bible.