More than 5,000 performances and translations into 17 languages leave little doubt that the off-Broadway musical I Love You, You're Perfect, Now Change hit a nerve with the theater community who vicariously enjoyed the trials and tribulations of their fellow humans in the ever-changing dating and mating turmoil of the late twentieth century. Life may be good, but there is this nagging feeling that something better could be just around the corner. Constancy is comfortable and calms the soul; change is exciting. Indeed, we know that nothing really stands still and that all is in flux, as Heraclitus of Ephesus proclaimed 2,500 years ago.

Except for the “Love You” part, it seems that nature has the same attitude toward its subjects and forces them to change without end. All species are in some way optimized and perfect, because they are clearly more successful than their competitors and survived for generation after generation where others did not. But this “optimal” is merely a current “optimal.” It resulted from unceasing change since life began and will most certainly transform into a new “optimal” in the future. Nature never stops exploring new options, and the only constant throughout the eons seems to have been change.

We all grow and age, and we really do not notice significant changes from one generation to the next, except, of course, that we are much more knowledgeable and sophisticated than all generations before us and most certainly incomparably wiser than our younger peers. But in spite of all evolutionary events, most of us have two eyes, two kidneys, and all those features that make us humans, and these just don't change, at least not fundamentally. Yes, we know that our roots go back to Neanderthals, Denisovans, Homo habilis, and early African hominids like Lucy, but those distant relatives disappeared a very long time ago. Evolution is a topic to be pondered among paleontologists and does not seem to have an urgent role in daily life.

It is actually not all that difficult to observe evolution at work. One only needs to start with a single bacterium and let it divide and multiply. All future cells should be the same, as there is no new source of genes. However, if we check merely a few weeks later, it is very likely that the genetic makeup of the population has become diverse.