Techno2000:
How about hypothetically a million lifetimes what would an observer see ?
I often consider this in my teaching. Imagine you had a small picture, the size of a postage stamp, of your mother, and she had one of her mother, and she one of hers, and so on, for a million lifetimes. And that these million stamp-sized pictures were all arranged, one after another, along a picket fence. Say each picture is three centimetres wide, so the whole line of pictures is three million centimetres, that’s thirty kilometres long. Or, if you like, each picture is projected onto a screen, each one facing into the next, every half second, taking nearly a week. At the start is your mother, at the end a thin, lemur-like monkey. Then all you have to do is to spot the points at which one species begins and another ends. Of course, it is impossible. The changes from one generation to the next, at any point, are so tiny that they are undetectable. That’s what evolution looks like.