GeologyRocks

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That's a great link, thanks!

Katie

Interesting article, thanks for sharing it.
Theres one thing I'm unsure about though:

Isn't an equally viable alternative that eyes weren't developed to the extent that they could distinguish these colours well)and therefore it was unimportant what colour these animals were. Colour could develop as a side effect of some other change in shell morphology/structure without it having an effect on the animal. Some compound eyes today can see in colour, but does anyone have any idea whether this was the case that far back?

Good point, Matt. However, certainly the prettiest looking fossils I've seen!

Jon

Matt, I don't think that he meant that colour developed because of eyes, in fact it's quite likely that colour probably did originate as some side effect or non-deleterious (meaning non-harmful/neutral) mutation as you say.

However, the fact that all these organisms had colour is suggestive that the colour was being selected upon. This would require sight as all the reasons I can think of for why you would want to be colourful require sight, i.e. species recognition, attracting mates (of the right species), camouflage and warning signals ("don't eat me I'm poisonous!"). Therefore it seems reasonable to deduce that the origination of all these different colours was linked to sight.

The ability of organisms to see colour may have set up some sort of evolutionary "arm's race" (the Red Queen Hypothesis), for example, as predators developed better and better vision, their prey became better and better at camouflaging themselves.