Huh? It's hard to make up a word that nobody has used on a webpage, ever. But apparently I did. I assume if you try that link in a few days/weeks/months? this page will then show up. [I checked a little over an hour later and this page was already there! I didn't realize google searched the web so continuously]. Anywho. I apologize to all cephalopod lovers for putting up the first video. But I believe it helps make three points:
1) You'll appreciate the selection pressure that led to video 2.
2) The evolution of shells and external skeletons led to so called 'adaptive radiations' in certain groups as they, temporarily, escaped their predators. This video shows the problems of the unarmored.
3) Remember one of the advantages of group living was being able to prey on larger or more difficult prey? I rest my case.
This next one is for the cephalopod lovers. You may have seen it before but it amazes me how the octopus mimics not just the colors but also the texture of the algae.