[Antoninus]

Here's one of my major problems with the ToE as it is currently formulated:



How is it that an organism like this can remain almost wholly unchanged for 140 million years? Is it not subject to genetic drift like everything else on the planet?

[Senator Bedfellow]

How is it that an organism like this can remain almost wholly unchanged for 140 million years? Is it not subject to genetic drift like everything else on the planet?

Sure it is, and of course the modern coelacanth is not the same species as the ancient fish - it has changed slightly since then.

Why not more change? If you're already well-adapted to your environment, and the environment doesn't change, then it becomes increasingly likely that any change will make you less well-adapted, and such changes will be selected against. So therefore, creatures that stick with the tried-and-true body plan will preferentially survive over radical newcomers who are less well-adapted, resulting in organisms that don't appear to change much over time.

It's not just coelacanths, either - sharks, cockroaches, dragonflies, ferns, and lots of other things haven't changed much in the last hundred million years either. If you have something that works, there's a strong incentive not to change.

[CarolinaGuitarman]

Not only is the modern coelacanth not the same species as the ancient ones, it's a different genus entirely. It has changed; there just has been any great selective pressure to change drastically. Organisms like the coelacanth and the shark are exceptional anyway.

[narby]

Here's one of my major problems with the ToE as it is currently formulated:

The Coelacanth is a classic stawman. Merely because creatures can evolve doesn't mean that they must.