I dreamed there was a news paper article with the headline, "The Nutroavailabitizer!"
Below the headline, there was a picture of a long skinny fish with a big weird bumpy appendage, almost as massive as the main fish, sticking up from its tail. The article was quoting a scientist who had concluded that the function of this big appendage was to take nutrients in the water in the stream where it lived, and convert them to a form that would be easier for the trees around the stream to use. In the dream, Iris asked me what I thought of that, and I said that it didn't make very much sense from an evolutionary perspective, because the fish would be putting enormous energy and resources into building and operating the filter thing, and it would make the fish much less streamlined, and in the end the only benefit the fish gets is healthier trees around the stream. I argued that if there was a mutation for not having that appendage, the mutant fish would still get the benefit of the healthier trees, because of the other fish still having the filters, but would not have to support the costs of having a filter itself. Likewise, if there were no fish with that filter, and one had a mutation that caused it, or an earlier version of it, only it would bear the costs but all would get the benefits, so it would be at a disadvantage again. Iris asked why I thought the fish did have it, and then my cellphone rang with a 7AM automated sales call.