Metamorphosis is something pretty different from gradually changing over time. Think about butterflies--at first the animal is a caterpillar, and then that same animal becomes a butterfly; which looks very different. This happens very quickly (days to weeks). Ancient "man" probably looked a lot different than we do today, but millions of years of gradual changes account for the difference.

Insect metamorphosis is pretty interesting.It takes a lot of specialized physiology and anatomy to let an animal turn from a caterpillar to a butterfly, or from a maggot to fly. This change is a lot different from the changes from early "almost humans" to humans, though. Insect metamorphosis takes place during the lifetime of *one individual*. Human evolution took place by offspring being a bit different from their parents. In evolution, the *population* changes over time. In metamorphosis, an *individual* changes in its own lifetime. If people are still around in a few hundred thousand years, they might be different from us, but *individual* humans still won't be able to turn into something else.

Why do you think insects can do metamorphosis and we can't? What is the advantage of having a crawling, eating body form for part of your life and a flying, mating body form for the other part? Are there disadvantages?

As a side note, the Neanderthals went extinct for unknown reasons about 35,000 years ago. Fossils suggests that we had the same ancestors they did, but we did not evolve from them. Fossil skulls show that Neanderthals had bigger brains than we do!

We humans don't metamorphize at all during our life. It is true that there have been big changes in humans over the time, but I am talking about millions of years. That means that human look has been changing from generation to generation : we are taller, we live longer, we look different than our great-great-great-great-great-great-(etc)-grandfather and -mother. Insects change over their life, from their birth to the end of their life; while humans, we just grow up.