Animal colourations and the patterns they generate provide some of the best examples of evolution by natural selection. One of the most studied aspects has been camouflage.
Colourblind people see colours differently because they do not have all the necessary information from the L, M and S cones. A simile would be to try to obtain different paint colours by mixing only two primary colours: we would never be able to obtain the full range of existing colours.
María Violeta Gómez Vicente, PhD in biochemistry and professor at the Department of Optics, Pharmacology, and Anatomy of the University of Alacant writes about the phenomenon of heterochromia.
When a material gets wet, we see it with a darker colour. Professor Inmaculada Pascual Villalobos explains why.