An unceasing flux

You share some of your genes with the tree through the window, but you and that tree parted company very early in eukaryotic evolution, 1.5 billion years ago, each following a different course permitted by different genes, the product of mutations, recombination and natural selection. You run around, and I hope still climb trees occasionally; they bend gently in the breeze and convert the air into more trees, the magic trick to end them all. All those differences are written in the genes, genes that derive from your common ancestor but have now mostly diverged beyond recognition... 

But that tree has mitochondria too, which work in much the same way as its chloroplasts, endlessly transferring electrons down its trillions upon trillions of respiratory chains, pumping protons across membranes as they always did. As you always did. These same shuttling electrons and protons have sustained you from the womb: you pump 10²¹  protons per second, every second, without pause.

from The Vital Question by Nick Lane (2015)

Image: Magus6 via wikicommons