Lacking the benefits of today’s powerful microscopes, Charles Darwin evidently thought of biological cells as simple — bounded but otherwise internally undifferentiated — blobs of organic matter.  Even when I was first learning about them, typical illustrations of the cell suggested (to my mind, at least) something resembling, say, an egg with a yolk.  Plain white matter, with something different inside.  Quite simple, really. Today, we know plant and animal cells to be almost incredibly complex, in both form... Read more