A lot of things, actually! I went for a short hike on Thursday and was struck by the diversity of white and filamentous structures in the forest. Filamentous – long strands are a common biological theme, because they join parts together or transport resources. White – many low atomic number materials (like nearly all biological tissue) reflect all colors of visible light, giving them a white or off-white appearance. Specialized colors for energy uptake (think chlorophyll) or warning coloration (think snake) are harder to evolve. Sometimes the most striking patterns are the simplest to explain. Here are three diverse examples of white things.
First, in a decomposing log, the web of a spider. This spider, which I never got to see, was sharing the tree with a colony of large ants.
Second, in the forest floor litter, the hyphae of a fungus. These hyphae (which together form a mycelium) are probing for new resources to use. In fungi, digestion happens outside its cells. Digestive enyzmes are secreted into the environment, and nutrients are then absorbed back into the cell. The more area the hyphae cover, the more resources that can be used. The branching structure might make you think of the network of veins in the human body, and the resource flow principles are indeed the same.
And finally, the protective covering of some sort of insect. Hairy yet pliant to the touch, almost like a stale marshmallow (if marshmallows were hairy). I didn’t want to cut it open and see if anyone was living inside, so we will have to leave this last one a mystery.
This post almost had a fourth picture, of some white markings on rocks near the island’s shore. However there have been recent crocodile maulings in the area and I decided to leave things be!